zig/lib/std/c.zig

const std = @import("std");
const builtin = @import("builtin");
const c = @This();
const maxInt = std.math.maxInt;
const assert = std.debug.assert;
const page_size = std.mem.page_size;
const native_abi = builtin.abi;
const native_arch = builtin.cpu.arch;
const native_os = builtin.os.tag;
const linux = std.os.linux;
const emscripten = std.os.emscripten;
const wasi = std.os.wasi;
const windows = std.os.windows;
const ws2_32 = std.os.windows.ws2_32;
const darwin = @import("c/darwin.zig");
const freebsd = @import("c/freebsd.zig");
const solaris = @import("c/solaris.zig");
const netbsd = @import("c/netbsd.zig");
const dragonfly = @import("c/dragonfly.zig");
const haiku = @import("c/haiku.zig");
const openbsd = @import("c/openbsd.zig");

// These constants are shared among all operating systems even when not linking
// libc.

pub const iovec = std.posix.iovec;
pub const iovec_const = std.posix.iovec_const;
pub const LOCK = std.posix.LOCK;
pub const winsize = std.posix.winsize;

/// The value of the link editor defined symbol _MH_EXECUTE_SYM is the address
/// of the mach header in a Mach-O executable file type.  It does not appear in
/// any file type other than a MH_EXECUTE file type.  The type of the symbol is
/// absolute as the header is not part of any section.
/// This symbol is populated when linking the system's libc, which is guaranteed
/// on this operating system. However when building object files or libraries,
/// the system libc won't be linked until the final executable. So we
/// export a weak symbol here, to be overridden by the real one.
pub extern var _mh_execute_header: mach_hdr;
var dummy_execute_header: mach_hdr = undefined;
comptime {
    if (native_os.isDarwin()) {
        @export(&dummy_execute_header, .{ .name = "_mh_execute_header", .linkage = .weak });
    }
}

/// If not linking libc, returns false.
/// If linking musl libc, returns true.
/// If linking gnu libc (glibc), returns true if the target version is greater
/// than or equal to `glibc_version`.
/// If linking a libc other than these, returns `false`.
pub inline fn versionCheck(comptime glibc_version: std.SemanticVersion) bool {
    return comptime blk: {
        if (!builtin.link_libc) break :blk false;
        if (native_abi.isMusl()) break :blk true;
        if (builtin.target.isGnuLibC()) {
            const ver = builtin.os.version_range.linux.glibc;
            const order = ver.order(glibc_version);
            break :blk switch (order) {
                .gt, .eq => true,
                .lt => false,
            };
        } else {
            break :blk false;
        }
    };
}

pub const ino_t = switch (native_os) {
    .linux => linux.ino_t,
    .emscripten => emscripten.ino_t,
    .wasi => wasi.inode_t,
    .windows => windows.LARGE_INTEGER,
    .haiku => i64,
    else => u64,
};

pub const off_t = switch (native_os) {
    .linux => linux.off_t,
    .emscripten => emscripten.off_t,
    else => i64,
};

pub const timespec = switch (native_os) {
    .linux => linux.timespec,
    .emscripten => emscripten.timespec,
    .wasi => extern struct {
        sec: time_t,
        nsec: isize,

        pub fn fromTimestamp(tm: wasi.timestamp_t) timespec {
            const sec: wasi.timestamp_t = tm / 1_000_000_000;
            const nsec = tm - sec * 1_000_000_000;
            return .{
                .sec = @as(time_t, @intCast(sec)),
                .nsec = @as(isize, @intCast(nsec)),
            };
        }

        pub fn toTimestamp(ts: timespec) wasi.timestamp_t {
            return @as(wasi.timestamp_t, @intCast(ts.sec * 1_000_000_000)) +
                @as(wasi.timestamp_t, @intCast(ts.nsec));
        }
    },
    .windows => extern struct {
        sec: time_t,
        nsec: c_long,
    },
    .dragonfly, .freebsd, .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        sec: isize,
        nsec: isize,
    },
    .netbsd, .solaris, .illumos => extern struct {
        sec: i64,
        nsec: isize,
    },
    .openbsd, .haiku => extern struct {
        sec: time_t,
        nsec: isize,
    },
    else => void,
};

pub const dev_t = switch (native_os) {
    .linux => linux.dev_t,
    .emscripten => emscripten.dev_t,
    .wasi => wasi.device_t,
    .openbsd, .haiku, .solaris, .illumos, .macos, .ios, .tvos, .watchos, .visionos => i32,
    .netbsd, .freebsd => u64,
    else => void,
};

pub const mode_t = switch (native_os) {
    .linux => linux.mode_t,
    .emscripten => emscripten.mode_t,
    .openbsd, .haiku, .netbsd, .solaris, .illumos, .wasi => u32,
    .freebsd, .macos, .ios, .tvos, .watchos, .visionos, .dragonfly => u16,
    else => u0,
};

pub const nlink_t = switch (native_os) {
    .linux => linux.nlink_t,
    .emscripten => emscripten.nlink_t,
    .wasi => c_ulonglong,
    .freebsd => u64,
    .openbsd, .netbsd, .solaris, .illumos => u32,
    .haiku => i32,
    else => void,
};

pub const uid_t = switch (native_os) {
    .linux => linux.uid_t,
    .emscripten => emscripten.uid_t,
    else => u32,
};

pub const gid_t = switch (native_os) {
    .linux => linux.gid_t,
    .emscripten => emscripten.gid_t,
    else => u32,
};

pub const blksize_t = switch (native_os) {
    .linux => linux.blksize_t,
    .emscripten => emscripten.blksize_t,
    .wasi => c_long,
    else => i32,
};

pub const passwd = switch (native_os) {
    .linux => extern struct {
        name: ?[*:0]const u8, // username
        passwd: ?[*:0]const u8, // user password
        uid: uid_t, // user ID
        gid: gid_t, // group ID
        gecos: ?[*:0]const u8, // user information
        dir: ?[*:0]const u8, // home directory
        shell: ?[*:0]const u8, // shell program
    },
    .netbsd, .openbsd, .macos => extern struct {
        name: ?[*:0]const u8, // user name
        passwd: ?[*:0]const u8, // encrypted password
        uid: uid_t, // user uid
        gid: gid_t, // user gid
        change: time_t, // password change time
        class: ?[*:0]const u8, // user access class
        gecos: ?[*:0]const u8, // Honeywell login info
        dir: ?[*:0]const u8, // home directory
        shell: ?[*:0]const u8, // default shell
        expire: time_t, // account expiration
    },
    else => void,
};

pub const blkcnt_t = switch (native_os) {
    .linux => linux.blkcnt_t,
    .emscripten => emscripten.blkcnt_t,
    .wasi => c_longlong,
    else => i64,
};

pub const fd_t = switch (native_os) {
    .linux => linux.fd_t,
    .wasi => wasi.fd_t,
    .windows => windows.HANDLE,
    else => i32,
};

pub const ARCH = switch (native_os) {
    .linux => linux.ARCH,
    else => void,
};
pub const CLOCK = clockid_t;
pub const clockid_t = switch (native_os) {
    .linux, .emscripten => linux.clockid_t,
    .wasi => wasi.clockid_t,
    .macos, .ios, .tvos, .watchos, .visionos => enum(u32) {
        REALTIME = 0,
        MONOTONIC = 6,
        MONOTONIC_RAW = 4,
        MONOTONIC_RAW_APPROX = 5,
        UPTIME_RAW = 8,
        UPTIME_RAW_APPROX = 9,
        PROCESS_CPUTIME_ID = 12,
        THREAD_CPUTIME_ID = 16,
        _,
    },
    .haiku => enum(i32) {
        /// system-wide monotonic clock (aka system time)
        MONOTONIC = 0,
        /// system-wide real time clock
        REALTIME = -1,
        /// clock measuring the used CPU time of the current process
        PROCESS_CPUTIME_ID = -2,
        /// clock measuring the used CPU time of the current thread
        THREAD_CPUTIME_ID = -3,
    },
    .freebsd => enum(u32) {
        REALTIME = 0,
        VIRTUAL = 1,
        PROF = 2,
        MONOTONIC = 4,
        UPTIME = 5,
        UPTIME_PRECISE = 7,
        UPTIME_FAST = 8,
        REALTIME_PRECISE = 9,
        REALTIME_FAST = 10,
        MONOTONIC_PRECISE = 11,
        MONOTONIC_FAST = 12,
        SECOND = 13,
        THREAD_CPUTIME_ID = 14,
        PROCESS_CPUTIME_ID = 15,
    },
    .solaris, .illumos => enum(u32) {
        VIRTUAL = 1,
        THREAD_CPUTIME_ID = 2,
        REALTIME = 3,
        MONOTONIC = 4,
        PROCESS_CPUTIME_ID = 5,
    },
    .netbsd => enum(u32) {
        REALTIME = 0,
        VIRTUAL = 1,
        PROF = 2,
        MONOTONIC = 3,
        THREAD_CPUTIME_ID = 0x20000000,
        PROCESS_CPUTIME_ID = 0x40000000,
    },
    .dragonfly => enum(u32) {
        REALTIME = 0,
        VIRTUAL = 1,
        PROF = 2,
        MONOTONIC = 4,
        UPTIME = 5,
        UPTIME_PRECISE = 7,
        UPTIME_FAST = 8,
        REALTIME_PRECISE = 9,
        REALTIME_FAST = 10,
        MONOTONIC_PRECISE = 11,
        MONOTONIC_FAST = 12,
        SECOND = 13,
        THREAD_CPUTIME_ID = 14,
        PROCESS_CPUTIME_ID = 15,
    },
    .openbsd => enum(u32) {
        REALTIME = 0,
        PROCESS_CPUTIME_ID = 2,
        MONOTONIC = 3,
        THREAD_CPUTIME_ID = 4,
    },
    else => void,
};
pub const CPU_COUNT = switch (native_os) {
    .linux => linux.CPU_COUNT,
    .emscripten => emscripten.CPU_COUNT,
    else => void,
};
pub const E = switch (native_os) {
    .linux => linux.E,
    .emscripten => emscripten.E,
    .wasi => wasi.errno_t,
    .windows => enum(u16) {
        /// No error occurred.
        SUCCESS = 0,
        PERM = 1,
        NOENT = 2,
        SRCH = 3,
        INTR = 4,
        IO = 5,
        NXIO = 6,
        @"2BIG" = 7,
        NOEXEC = 8,
        BADF = 9,
        CHILD = 10,
        AGAIN = 11,
        NOMEM = 12,
        ACCES = 13,
        FAULT = 14,
        BUSY = 16,
        EXIST = 17,
        XDEV = 18,
        NODEV = 19,
        NOTDIR = 20,
        ISDIR = 21,
        NFILE = 23,
        MFILE = 24,
        NOTTY = 25,
        FBIG = 27,
        NOSPC = 28,
        SPIPE = 29,
        ROFS = 30,
        MLINK = 31,
        PIPE = 32,
        DOM = 33,
        /// Also means `DEADLOCK`.
        DEADLK = 36,
        NAMETOOLONG = 38,
        NOLCK = 39,
        NOSYS = 40,
        NOTEMPTY = 41,

        INVAL = 22,
        RANGE = 34,
        ILSEQ = 42,

        // POSIX Supplement
        ADDRINUSE = 100,
        ADDRNOTAVAIL = 101,
        AFNOSUPPORT = 102,
        ALREADY = 103,
        BADMSG = 104,
        CANCELED = 105,
        CONNABORTED = 106,
        CONNREFUSED = 107,
        CONNRESET = 108,
        DESTADDRREQ = 109,
        HOSTUNREACH = 110,
        IDRM = 111,
        INPROGRESS = 112,
        ISCONN = 113,
        LOOP = 114,
        MSGSIZE = 115,
        NETDOWN = 116,
        NETRESET = 117,
        NETUNREACH = 118,
        NOBUFS = 119,
        NODATA = 120,
        NOLINK = 121,
        NOMSG = 122,
        NOPROTOOPT = 123,
        NOSR = 124,
        NOSTR = 125,
        NOTCONN = 126,
        NOTRECOVERABLE = 127,
        NOTSOCK = 128,
        NOTSUP = 129,
        OPNOTSUPP = 130,
        OTHER = 131,
        OVERFLOW = 132,
        OWNERDEAD = 133,
        PROTO = 134,
        PROTONOSUPPORT = 135,
        PROTOTYPE = 136,
        TIME = 137,
        TIMEDOUT = 138,
        TXTBSY = 139,
        WOULDBLOCK = 140,
        DQUOT = 10069,
        _,
    },
    .macos, .ios, .tvos, .watchos, .visionos => darwin.E,
    .freebsd => freebsd.E,
    .solaris, .illumos => enum(u16) {
        /// No error occurred.
        SUCCESS = 0,
        /// Not super-user
        PERM = 1,
        /// No such file or directory
        NOENT = 2,
        /// No such process
        SRCH = 3,
        /// interrupted system call
        INTR = 4,
        /// I/O error
        IO = 5,
        /// No such device or address
        NXIO = 6,
        /// Arg list too long
        @"2BIG" = 7,
        /// Exec format error
        NOEXEC = 8,
        /// Bad file number
        BADF = 9,
        /// No children
        CHILD = 10,
        /// Resource temporarily unavailable.
        /// also: WOULDBLOCK: Operation would block.
        AGAIN = 11,
        /// Not enough core
        NOMEM = 12,
        /// Permission denied
        ACCES = 13,
        /// Bad address
        FAULT = 14,
        /// Block device required
        NOTBLK = 15,
        /// Mount device busy
        BUSY = 16,
        /// File exists
        EXIST = 17,
        /// Cross-device link
        XDEV = 18,
        /// No such device
        NODEV = 19,
        /// Not a directory
        NOTDIR = 20,
        /// Is a directory
        ISDIR = 21,
        /// Invalid argument
        INVAL = 22,
        /// File table overflow
        NFILE = 23,
        /// Too many open files
        MFILE = 24,
        /// Inappropriate ioctl for device
        NOTTY = 25,
        /// Text file busy
        TXTBSY = 26,
        /// File too large
        FBIG = 27,
        /// No space left on device
        NOSPC = 28,
        /// Illegal seek
        SPIPE = 29,
        /// Read only file system
        ROFS = 30,
        /// Too many links
        MLINK = 31,
        /// Broken pipe
        PIPE = 32,
        /// Math arg out of domain of func
        DOM = 33,
        /// Math result not representable
        RANGE = 34,
        /// No message of desired type
        NOMSG = 35,
        /// Identifier removed
        IDRM = 36,
        /// Channel number out of range
        CHRNG = 37,
        /// Level 2 not synchronized
        L2NSYNC = 38,
        /// Level 3 halted
        L3HLT = 39,
        /// Level 3 reset
        L3RST = 40,
        /// Link number out of range
        LNRNG = 41,
        /// Protocol driver not attached
        UNATCH = 42,
        /// No CSI structure available
        NOCSI = 43,
        /// Level 2 halted
        L2HLT = 44,
        /// Deadlock condition.
        DEADLK = 45,
        /// No record locks available.
        NOLCK = 46,
        /// Operation canceled
        CANCELED = 47,
        /// Operation not supported
        NOTSUP = 48,

        // Filesystem Quotas
        /// Disc quota exceeded
        DQUOT = 49,

        // Convergent Error Returns
        /// invalid exchange
        BADE = 50,
        /// invalid request descriptor
        BADR = 51,
        /// exchange full
        XFULL = 52,
        /// no anode
        NOANO = 53,
        /// invalid request code
        BADRQC = 54,
        /// invalid slot
        BADSLT = 55,
        /// file locking deadlock error
        DEADLOCK = 56,
        /// bad font file fmt
        BFONT = 57,

        // Interprocess Robust Locks
        /// process died with the lock
        OWNERDEAD = 58,
        /// lock is not recoverable
        NOTRECOVERABLE = 59,
        /// locked lock was unmapped
        LOCKUNMAPPED = 72,
        /// Facility is not active
        NOTACTIVE = 73,
        /// multihop attempted
        MULTIHOP = 74,
        /// trying to read unreadable message
        BADMSG = 77,
        /// path name is too long
        NAMETOOLONG = 78,
        /// value too large to be stored in data type
        OVERFLOW = 79,
        /// given log. name not unique
        NOTUNIQ = 80,
        /// f.d. invalid for this operation
        BADFD = 81,
        /// Remote address changed
        REMCHG = 82,

        // Stream Problems
        /// Device not a stream
        NOSTR = 60,
        /// no data (for no delay io)
        NODATA = 61,
        /// timer expired
        TIME = 62,
        /// out of streams resources
        NOSR = 63,
        /// Machine is not on the network
        NONET = 64,
        /// Package not installed
        NOPKG = 65,
        /// The object is remote
        REMOTE = 66,
        /// the link has been severed
        NOLINK = 67,
        /// advertise error
        ADV = 68,
        /// srmount error
        SRMNT = 69,
        /// Communication error on send
        COMM = 70,
        /// Protocol error
        PROTO = 71,

        // Shared Library Problems
        /// Can't access a needed shared lib.
        LIBACC = 83,
        /// Accessing a corrupted shared lib.
        LIBBAD = 84,
        /// .lib section in a.out corrupted.
        LIBSCN = 85,
        /// Attempting to link in too many libs.
        LIBMAX = 86,
        /// Attempting to exec a shared library.
        LIBEXEC = 87,
        /// Illegal byte sequence.
        ILSEQ = 88,
        /// Unsupported file system operation
        NOSYS = 89,
        /// Symbolic link loop
        LOOP = 90,
        /// Restartable system call
        RESTART = 91,
        /// if pipe/FIFO, don't sleep in stream head
        STRPIPE = 92,
        /// directory not empty
        NOTEMPTY = 93,
        /// Too many users (for UFS)
        USERS = 94,

        // BSD Networking Software
        // Argument Errors
        /// Socket operation on non-socket
        NOTSOCK = 95,
        /// Destination address required
        DESTADDRREQ = 96,
        /// Message too long
        MSGSIZE = 97,
        /// Protocol wrong type for socket
        PROTOTYPE = 98,
        /// Protocol not available
        NOPROTOOPT = 99,
        /// Protocol not supported
        PROTONOSUPPORT = 120,
        /// Socket type not supported
        SOCKTNOSUPPORT = 121,
        /// Operation not supported on socket
        OPNOTSUPP = 122,
        /// Protocol family not supported
        PFNOSUPPORT = 123,
        /// Address family not supported by
        AFNOSUPPORT = 124,
        /// Address already in use
        ADDRINUSE = 125,
        /// Can't assign requested address
        ADDRNOTAVAIL = 126,

        // Operational Errors
        /// Network is down
        NETDOWN = 127,
        /// Network is unreachable
        NETUNREACH = 128,
        /// Network dropped connection because
        NETRESET = 129,
        /// Software caused connection abort
        CONNABORTED = 130,
        /// Connection reset by peer
        CONNRESET = 131,
        /// No buffer space available
        NOBUFS = 132,
        /// Socket is already connected
        ISCONN = 133,
        /// Socket is not connected
        NOTCONN = 134,
        /// Can't send after socket shutdown
        SHUTDOWN = 143,
        /// Too many references: can't splice
        TOOMANYREFS = 144,
        /// Connection timed out
        TIMEDOUT = 145,
        /// Connection refused
        CONNREFUSED = 146,
        /// Host is down
        HOSTDOWN = 147,
        /// No route to host
        HOSTUNREACH = 148,
        /// operation already in progress
        ALREADY = 149,
        /// operation now in progress
        INPROGRESS = 150,

        // SUN Network File System
        /// Stale NFS file handle
        STALE = 151,

        _,
    },
    .netbsd => netbsd.E,
    .dragonfly => dragonfly.E,
    .haiku => haiku.E,
    .openbsd => openbsd.E,
    else => void,
};
pub const Elf_Symndx = switch (native_os) {
    .linux => linux.Elf_Symndx,
    else => void,
};
/// Command flags for fcntl(2).
pub const F = switch (native_os) {
    .linux => linux.F,
    .emscripten => emscripten.F,
    .wasi => struct {
        pub const GETFD = 1;
        pub const SETFD = 2;
        pub const GETFL = 3;
        pub const SETFL = 4;
    },
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        /// duplicate file descriptor
        pub const DUPFD = 0;
        /// get file descriptor flags
        pub const GETFD = 1;
        /// set file descriptor flags
        pub const SETFD = 2;
        /// get file status flags
        pub const GETFL = 3;
        /// set file status flags
        pub const SETFL = 4;
        /// get SIGIO/SIGURG proc/pgrp
        pub const GETOWN = 5;
        /// set SIGIO/SIGURG proc/pgrp
        pub const SETOWN = 6;
        /// get record locking information
        pub const GETLK = 7;
        /// set record locking information
        pub const SETLK = 8;
        /// F.SETLK; wait if blocked
        pub const SETLKW = 9;
        /// F.SETLK; wait if blocked, return on timeout
        pub const SETLKWTIMEOUT = 10;
        pub const FLUSH_DATA = 40;
        /// Used for regression test
        pub const CHKCLEAN = 41;
        /// Preallocate storage
        pub const PREALLOCATE = 42;
        /// Truncate a file without zeroing space
        pub const SETSIZE = 43;
        /// Issue an advisory read async with no copy to user
        pub const RDADVISE = 44;
        /// turn read ahead off/on for this fd
        pub const RDAHEAD = 45;
        /// turn data caching off/on for this fd
        pub const NOCACHE = 48;
        /// file offset to device offset
        pub const LOG2PHYS = 49;
        /// return the full path of the fd
        pub const GETPATH = 50;
        /// fsync + ask the drive to flush to the media
        pub const FULLFSYNC = 51;
        /// find which component (if any) is a package
        pub const PATHPKG_CHECK = 52;
        /// "freeze" all fs operations
        pub const FREEZE_FS = 53;
        /// "thaw" all fs operations
        pub const THAW_FS = 54;
        /// turn data caching off/on (globally) for this file
        pub const GLOBAL_NOCACHE = 55;
        /// add detached signatures
        pub const ADDSIGS = 59;
        /// add signature from same file (used by dyld for shared libs)
        pub const ADDFILESIGS = 61;
        /// used in conjunction with F.NOCACHE to indicate that DIRECT, synchronous writes
        /// should not be used (i.e. its ok to temporarily create cached pages)
        pub const NODIRECT = 62;
        /// Get the protection class of a file from the EA, returns int
        pub const GETPROTECTIONCLASS = 63;
        /// Set the protection class of a file for the EA, requires int
        pub const SETPROTECTIONCLASS = 64;
        /// file offset to device offset, extended
        pub const LOG2PHYS_EXT = 65;
        /// get record locking information, per-process
        pub const GETLKPID = 66;
        /// Mark the file as being the backing store for another filesystem
        pub const SETBACKINGSTORE = 70;
        /// return the full path of the FD, but error in specific mtmd circumstances
        pub const GETPATH_MTMINFO = 71;
        /// Returns the code directory, with associated hashes, to the caller
        pub const GETCODEDIR = 72;
        /// No SIGPIPE generated on EPIPE
        pub const SETNOSIGPIPE = 73;
        /// Status of SIGPIPE for this fd
        pub const GETNOSIGPIPE = 74;
        /// For some cases, we need to rewrap the key for AKS/MKB
        pub const TRANSCODEKEY = 75;
        /// file being written to a by single writer... if throttling enabled, writes
        /// may be broken into smaller chunks with throttling in between
        pub const SINGLE_WRITER = 76;
        /// Get the protection version number for this filesystem
        pub const GETPROTECTIONLEVEL = 77;
        /// Add detached code signatures (used by dyld for shared libs)
        pub const FINDSIGS = 78;
        /// Add signature from same file, only if it is signed by Apple (used by dyld for simulator)
        pub const ADDFILESIGS_FOR_DYLD_SIM = 83;
        /// fsync + issue barrier to drive
        pub const BARRIERFSYNC = 85;
        /// Add signature from same file, return end offset in structure on success
        pub const ADDFILESIGS_RETURN = 97;
        /// Check if Library Validation allows this Mach-O file to be mapped into the calling process
        pub const CHECK_LV = 98;
        /// Deallocate a range of the file
        pub const PUNCHHOLE = 99;
        /// Trim an active file
        pub const TRIM_ACTIVE_FILE = 100;
        /// mark the dup with FD_CLOEXEC
        pub const DUPFD_CLOEXEC = 67;
        /// shared or read lock
        pub const RDLCK = 1;
        /// unlock
        pub const UNLCK = 2;
        /// exclusive or write lock
        pub const WRLCK = 3;
    },
    .freebsd => struct {
        /// Duplicate file descriptor.
        pub const DUPFD = 0;
        /// Get file descriptor flags.
        pub const GETFD = 1;
        /// Set file descriptor flags.
        pub const SETFD = 2;
        /// Get file status flags.
        pub const GETFL = 3;
        /// Set file status flags.
        pub const SETFL = 4;

        /// Get SIGIO/SIGURG proc/pgrrp.
        pub const GETOWN = 5;
        /// Set SIGIO/SIGURG proc/pgrrp.
        pub const SETOWN = 6;

        /// Get record locking information.
        pub const GETLK = 11;
        /// Set record locking information.
        pub const SETLK = 12;
        /// Set record locking information and wait if blocked.
        pub const SETLKW = 13;

        /// Debugging support for remote locks.
        pub const SETLK_REMOTE = 14;
        /// Read ahead.
        pub const READAHEAD = 15;

        /// DUPFD with FD_CLOEXEC set.
        pub const DUPFD_CLOEXEC = 17;
        /// DUP2FD with FD_CLOEXEC set.
        pub const DUP2FD_CLOEXEC = 18;

        pub const ADD_SEALS = 19;
        pub const GET_SEALS = 20;
        /// Return `kinfo_file` for a file descriptor.
        pub const KINFO = 22;

        // Seals (ADD_SEALS, GET_SEALS)
        /// Prevent adding sealings.
        pub const SEAL_SEAL = 0x0001;
        /// May not shrink
        pub const SEAL_SHRINK = 0x0002;
        /// May not grow.
        pub const SEAL_GROW = 0x0004;
        /// May not write.
        pub const SEAL_WRITE = 0x0008;

        // Record locking flags (GETLK, SETLK, SETLKW).
        /// Shared or read lock.
        pub const RDLCK = 1;
        /// Unlock.
        pub const UNLCK = 2;
        /// Exclusive or write lock.
        pub const WRLCK = 3;
        /// Purge locks for a given system ID.
        pub const UNLCKSYS = 4;
        /// Cancel an async lock request.
        pub const CANCEL = 5;

        pub const SETOWN_EX = 15;
        pub const GETOWN_EX = 16;

        pub const GETOWNER_UIDS = 17;
    },
    .solaris, .illumos => struct {
        /// Unlock a previously locked region
        pub const ULOCK = 0;
        /// Lock a region for exclusive use
        pub const LOCK = 1;
        /// Test and lock a region for exclusive use
        pub const TLOCK = 2;
        /// Test a region for other processes locks
        pub const TEST = 3;

        /// Duplicate fildes
        pub const DUPFD = 0;
        /// Get fildes flags
        pub const GETFD = 1;
        /// Set fildes flags
        pub const SETFD = 2;
        /// Get file flags
        pub const GETFL = 3;
        /// Get file flags including open-only flags
        pub const GETXFL = 45;
        /// Set file flags
        pub const SETFL = 4;

        /// Unused
        pub const CHKFL = 8;
        /// Duplicate fildes at third arg
        pub const DUP2FD = 9;
        /// Like DUP2FD with O_CLOEXEC set EINVAL is fildes matches arg1
        pub const DUP2FD_CLOEXEC = 36;
        /// Like DUPFD with O_CLOEXEC set
        pub const DUPFD_CLOEXEC = 37;

        /// Is the file desc. a stream ?
        pub const ISSTREAM = 13;
        /// Turn on private access to file
        pub const PRIV = 15;
        /// Turn off private access to file
        pub const NPRIV = 16;
        /// UFS quota call
        pub const QUOTACTL = 17;
        /// Get number of BLKSIZE blocks allocated
        pub const BLOCKS = 18;
        /// Get optimal I/O block size
        pub const BLKSIZE = 19;
        /// Get owner (socket emulation)
        pub const GETOWN = 23;
        /// Set owner (socket emulation)
        pub const SETOWN = 24;
        /// Object reuse revoke access to file desc.
        pub const REVOKE = 25;
        /// Does vp have NFS locks private to lock manager
        pub const HASREMOTELOCKS = 26;

        /// Set file lock
        pub const SETLK = 6;
        /// Set file lock and wait
        pub const SETLKW = 7;
        /// Allocate file space
        pub const ALLOCSP = 10;
        /// Free file space
        pub const FREESP = 11;
        /// Get file lock
        pub const GETLK = 14;
        /// Get file lock owned by file
        pub const OFD_GETLK = 47;
        /// Set file lock owned by file
        pub const OFD_SETLK = 48;
        /// Set file lock owned by file and wait
        pub const OFD_SETLKW = 49;
        /// Set a file share reservation
        pub const SHARE = 40;
        /// Remove a file share reservation
        pub const UNSHARE = 41;
        /// Create Poison FD
        pub const BADFD = 46;

        /// Read lock
        pub const RDLCK = 1;
        /// Write lock
        pub const WRLCK = 2;
        /// Remove lock(s)
        pub const UNLCK = 3;
        /// remove remote locks for a given system
        pub const UNLKSYS = 4;

        // f_access values
        /// Read-only share access
        pub const RDACC = 0x1;
        /// Write-only share access
        pub const WRACC = 0x2;
        /// Read-Write share access
        pub const RWACC = 0x3;

        // f_deny values
        /// Don't deny others access
        pub const NODNY = 0x0;
        /// Deny others read share access
        pub const RDDNY = 0x1;
        /// Deny others write share access
        pub const WRDNY = 0x2;
        /// Deny others read or write share access
        pub const RWDNY = 0x3;
        /// private flag: Deny delete share access
        pub const RMDNY = 0x4;
    },
    .netbsd => struct {
        pub const DUPFD = 0;
        pub const GETFD = 1;
        pub const SETFD = 2;
        pub const GETFL = 3;
        pub const SETFL = 4;
        pub const GETOWN = 5;
        pub const SETOWN = 6;
        pub const GETLK = 7;
        pub const SETLK = 8;
        pub const SETLKW = 9;
        pub const CLOSEM = 10;
        pub const MAXFD = 11;
        pub const DUPFD_CLOEXEC = 12;
        pub const GETNOSIGPIPE = 13;
        pub const SETNOSIGPIPE = 14;
        pub const GETPATH = 15;

        pub const RDLCK = 1;
        pub const WRLCK = 3;
        pub const UNLCK = 2;
    },
    .dragonfly => struct {
        pub const ULOCK = 0;
        pub const LOCK = 1;
        pub const TLOCK = 2;
        pub const TEST = 3;

        pub const DUPFD = 0;
        pub const GETFD = 1;
        pub const RDLCK = 1;
        pub const SETFD = 2;
        pub const UNLCK = 2;
        pub const WRLCK = 3;
        pub const GETFL = 3;
        pub const SETFL = 4;
        pub const GETOWN = 5;
        pub const SETOWN = 6;
        pub const GETLK = 7;
        pub const SETLK = 8;
        pub const SETLKW = 9;
        pub const DUP2FD = 10;
        pub const DUPFD_CLOEXEC = 17;
        pub const DUP2FD_CLOEXEC = 18;
        pub const GETPATH = 19;
    },
    .haiku => struct {
        pub const DUPFD = 0x0001;
        pub const GETFD = 0x0002;
        pub const SETFD = 0x0004;
        pub const GETFL = 0x0008;
        pub const SETFL = 0x0010;

        pub const GETLK = 0x0020;
        pub const SETLK = 0x0080;
        pub const SETLKW = 0x0100;
        pub const DUPFD_CLOEXEC = 0x0200;

        pub const RDLCK = 0x0040;
        pub const UNLCK = 0x0200;
        pub const WRLCK = 0x0400;
    },
    .openbsd => struct {
        pub const DUPFD = 0;
        pub const GETFD = 1;
        pub const SETFD = 2;
        pub const GETFL = 3;
        pub const SETFL = 4;

        pub const GETOWN = 5;
        pub const SETOWN = 6;

        pub const GETLK = 7;
        pub const SETLK = 8;
        pub const SETLKW = 9;

        pub const RDLCK = 1;
        pub const UNLCK = 2;
        pub const WRLCK = 3;
    },
    else => void,
};
pub const FD_CLOEXEC = switch (native_os) {
    .linux => linux.FD_CLOEXEC,
    .emscripten => emscripten.FD_CLOEXEC,
    else => 1,
};

/// Test for existence of file.
pub const F_OK = switch (native_os) {
    .linux => linux.F_OK,
    .emscripten => emscripten.F_OK,
    else => 0,
};
/// Test for execute or search permission.
pub const X_OK = switch (native_os) {
    .linux => linux.X_OK,
    .emscripten => emscripten.X_OK,
    else => 1,
};
/// Test for write permission.
pub const W_OK = switch (native_os) {
    .linux => linux.W_OK,
    .emscripten => emscripten.W_OK,
    else => 2,
};
/// Test for read permission.
pub const R_OK = switch (native_os) {
    .linux => linux.R_OK,
    .emscripten => emscripten.R_OK,
    else => 4,
};

pub const Flock = switch (native_os) {
    .linux => linux.Flock,
    .emscripten => emscripten.Flock,
    .openbsd, .dragonfly, .netbsd, .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        start: off_t,
        len: off_t,
        pid: pid_t,
        type: i16,
        whence: i16,
    },
    .freebsd => extern struct {
        /// Starting offset.
        start: off_t,
        /// Number of consecutive bytes to be locked.
        /// A value of 0 means to the end of the file.
        len: off_t,
        /// Lock owner.
        pid: pid_t,
        /// Lock type.
        type: i16,
        /// Type of the start member.
        whence: i16,
        /// Remote system id or zero for local.
        sysid: i32,
    },
    .solaris, .illumos => extern struct {
        type: c_short,
        whence: c_short,
        start: off_t,
        // len == 0 means until end of file.
        len: off_t,
        sysid: c_int,
        pid: pid_t,
        __pad: [4]c_long,
    },
    .haiku => extern struct {
        type: i16,
        whence: i16,
        start: off_t,
        len: off_t,
        pid: pid_t,
    },
    else => void,
};
pub const HOST_NAME_MAX = switch (native_os) {
    .linux => linux.HOST_NAME_MAX,
    .macos, .ios, .tvos, .watchos, .visionos => 72,
    .openbsd, .haiku, .dragonfly, .netbsd, .solaris, .illumos, .freebsd => 255,
    else => {},
};
pub const IOV_MAX = switch (native_os) {
    .linux => linux.IOV_MAX,
    .emscripten => emscripten.IOV_MAX,
    .openbsd, .haiku, .solaris, .illumos, .wasi => 1024,
    .macos, .ios, .tvos, .watchos, .visionos => 16,
    .dragonfly, .netbsd, .freebsd => KERN.IOV_MAX,
    else => {},
};
pub const CTL = switch (native_os) {
    .freebsd => struct {
        pub const KERN = 1;
        pub const DEBUG = 5;
    },
    .netbsd => struct {
        pub const KERN = 1;
        pub const DEBUG = 5;
    },
    .dragonfly => struct {
        pub const UNSPEC = 0;
        pub const KERN = 1;
        pub const VM = 2;
        pub const VFS = 3;
        pub const NET = 4;
        pub const DEBUG = 5;
        pub const HW = 6;
        pub const MACHDEP = 7;
        pub const USER = 8;
        pub const LWKT = 10;
        pub const MAXID = 11;
        pub const MAXNAME = 12;
    },
    .openbsd => struct {
        pub const UNSPEC = 0;
        pub const KERN = 1;
        pub const VM = 2;
        pub const FS = 3;
        pub const NET = 4;
        pub const DEBUG = 5;
        pub const HW = 6;
        pub const MACHDEP = 7;

        pub const DDB = 9;
        pub const VFS = 10;
    },
    else => void,
};
pub const KERN = switch (native_os) {
    .freebsd => struct {
        /// struct: process entries
        pub const PROC = 14;
        /// path to executable
        pub const PROC_PATHNAME = 12;
        /// file descriptors for process
        pub const PROC_FILEDESC = 33;
        pub const IOV_MAX = 35;
    },
    .netbsd => struct {
        /// struct: process argv/env
        pub const PROC_ARGS = 48;
        /// path to executable
        pub const PROC_PATHNAME = 5;
        pub const IOV_MAX = 38;
    },
    .dragonfly => struct {
        pub const PROC_ALL = 0;
        pub const OSTYPE = 1;
        pub const PROC_PID = 1;
        pub const OSRELEASE = 2;
        pub const PROC_PGRP = 2;
        pub const OSREV = 3;
        pub const PROC_SESSION = 3;
        pub const VERSION = 4;
        pub const PROC_TTY = 4;
        pub const MAXVNODES = 5;
        pub const PROC_UID = 5;
        pub const MAXPROC = 6;
        pub const PROC_RUID = 6;
        pub const MAXFILES = 7;
        pub const PROC_ARGS = 7;
        pub const ARGMAX = 8;
        pub const PROC_CWD = 8;
        pub const PROC_PATHNAME = 9;
        pub const SECURELVL = 9;
        pub const PROC_SIGTRAMP = 10;
        pub const HOSTNAME = 10;
        pub const HOSTID = 11;
        pub const CLOCKRATE = 12;
        pub const VNODE = 13;
        pub const PROC = 14;
        pub const FILE = 15;
        pub const PROC_FLAGMASK = 16;
        pub const PROF = 16;
        pub const PROC_FLAG_LWP = 16;
        pub const POSIX1 = 17;
        pub const NGROUPS = 18;
        pub const JOB_CONTROL = 19;
        pub const SAVED_IDS = 20;
        pub const BOOTTIME = 21;
        pub const NISDOMAINNAME = 22;
        pub const UPDATEINTERVAL = 23;
        pub const OSRELDATE = 24;
        pub const NTP_PLL = 25;
        pub const BOOTFILE = 26;
        pub const MAXFILESPERPROC = 27;
        pub const MAXPROCPERUID = 28;
        pub const DUMPDEV = 29;
        pub const IPC = 30;
        pub const DUMMY = 31;
        pub const PS_STRINGS = 32;
        pub const USRSTACK = 33;
        pub const LOGSIGEXIT = 34;
        pub const IOV_MAX = 35;
        pub const MAXPOSIXLOCKSPERUID = 36;
        pub const MAXID = 37;
    },
    .openbsd => struct {
        pub const OSTYPE = 1;
        pub const OSRELEASE = 2;
        pub const OSREV = 3;
        pub const VERSION = 4;
        pub const MAXVNODES = 5;
        pub const MAXPROC = 6;
        pub const MAXFILES = 7;
        pub const ARGMAX = 8;
        pub const SECURELVL = 9;
        pub const HOSTNAME = 10;
        pub const HOSTID = 11;
        pub const CLOCKRATE = 12;

        pub const PROF = 16;
        pub const POSIX1 = 17;
        pub const NGROUPS = 18;
        pub const JOB_CONTROL = 19;
        pub const SAVED_IDS = 20;
        pub const BOOTTIME = 21;
        pub const DOMAINNAME = 22;
        pub const MAXPARTITIONS = 23;
        pub const RAWPARTITION = 24;
        pub const MAXTHREAD = 25;
        pub const NTHREADS = 26;
        pub const OSVERSION = 27;
        pub const SOMAXCONN = 28;
        pub const SOMINCONN = 29;

        pub const NOSUIDCOREDUMP = 32;
        pub const FSYNC = 33;
        pub const SYSVMSG = 34;
        pub const SYSVSEM = 35;
        pub const SYSVSHM = 36;

        pub const MSGBUFSIZE = 38;
        pub const MALLOCSTATS = 39;
        pub const CPTIME = 40;
        pub const NCHSTATS = 41;
        pub const FORKSTAT = 42;
        pub const NSELCOLL = 43;
        pub const TTY = 44;
        pub const CCPU = 45;
        pub const FSCALE = 46;
        pub const NPROCS = 47;
        pub const MSGBUF = 48;
        pub const POOL = 49;
        pub const STACKGAPRANDOM = 50;
        pub const SYSVIPC_INFO = 51;
        pub const ALLOWKMEM = 52;
        pub const WITNESSWATCH = 53;
        pub const SPLASSERT = 54;
        pub const PROC_ARGS = 55;
        pub const NFILES = 56;
        pub const TTYCOUNT = 57;
        pub const NUMVNODES = 58;
        pub const MBSTAT = 59;
        pub const WITNESS = 60;
        pub const SEMINFO = 61;
        pub const SHMINFO = 62;
        pub const INTRCNT = 63;
        pub const WATCHDOG = 64;
        pub const ALLOWDT = 65;
        pub const PROC = 66;
        pub const MAXCLUSTERS = 67;
        pub const EVCOUNT = 68;
        pub const TIMECOUNTER = 69;
        pub const MAXLOCKSPERUID = 70;
        pub const CPTIME2 = 71;
        pub const CACHEPCT = 72;
        pub const FILE = 73;
        pub const WXABORT = 74;
        pub const CONSDEV = 75;
        pub const NETLIVELOCKS = 76;
        pub const POOL_DEBUG = 77;
        pub const PROC_CWD = 78;
        pub const PROC_NOBROADCASTKILL = 79;
        pub const PROC_VMMAP = 80;
        pub const GLOBAL_PTRACE = 81;
        pub const CONSBUFSIZE = 82;
        pub const CONSBUF = 83;
        pub const AUDIO = 84;
        pub const CPUSTATS = 85;
        pub const PFSTATUS = 86;
        pub const TIMEOUT_STATS = 87;
        pub const UTC_OFFSET = 88;
        pub const VIDEO = 89;

        pub const PROC_ALL = 0;
        pub const PROC_PID = 1;
        pub const PROC_PGRP = 2;
        pub const PROC_SESSION = 3;
        pub const PROC_TTY = 4;
        pub const PROC_UID = 5;
        pub const PROC_RUID = 6;
        pub const PROC_KTHREAD = 7;
        pub const PROC_SHOW_THREADS = 0x40000000;

        pub const PROC_ARGV = 1;
        pub const PROC_NARGV = 2;
        pub const PROC_ENV = 3;
        pub const PROC_NENV = 4;
    },
    else => void,
};
pub const MADV = switch (native_os) {
    .linux => linux.MADV,
    .emscripten => emscripten.MADV,
    .freebsd => struct {
        pub const NORMAL = 0;
        pub const RANDOM = 1;
        pub const SEQUENTIAL = 2;
        pub const WILLNEED = 3;
        pub const DONTNEED = 4;
        pub const FREE = 5;
        pub const NOSYNC = 6;
        pub const AUTOSYNC = 7;
        pub const NOCORE = 8;
        pub const CORE = 9;
        pub const PROTECT = 10;
    },
    .solaris, .illumos => struct {
        /// no further special treatment
        pub const NORMAL = 0;
        /// expect random page references
        pub const RANDOM = 1;
        /// expect sequential page references
        pub const SEQUENTIAL = 2;
        /// will need these pages
        pub const WILLNEED = 3;
        /// don't need these pages
        pub const DONTNEED = 4;
        /// contents can be freed
        pub const FREE = 5;
        /// default access
        pub const ACCESS_DEFAULT = 6;
        /// next LWP to access heavily
        pub const ACCESS_LWP = 7;
        /// many processes to access heavily
        pub const ACCESS_MANY = 8;
        /// contents will be purged
        pub const PURGE = 9;
    },
    .dragonfly => struct {
        pub const SEQUENTIAL = 2;
        pub const CONTROL_END = SETMAP;
        pub const DONTNEED = 4;
        pub const RANDOM = 1;
        pub const WILLNEED = 3;
        pub const NORMAL = 0;
        pub const CONTROL_START = INVAL;
        pub const FREE = 5;
        pub const NOSYNC = 6;
        pub const AUTOSYNC = 7;
        pub const NOCORE = 8;
        pub const CORE = 9;
        pub const INVAL = 10;
        pub const SETMAP = 11;
    },
    else => void,
};
pub const MSF = switch (native_os) {
    .linux => linux.MSF,
    .emscripten => emscripten.MSF,
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const ASYNC = 0x1;
        pub const INVALIDATE = 0x2;
        /// invalidate, leave mapped
        pub const KILLPAGES = 0x4;
        /// deactivate, leave mapped
        pub const DEACTIVATE = 0x8;
        pub const SYNC = 0x10;
    },
    .openbsd, .haiku, .dragonfly, .netbsd, .solaris, .illumos, .freebsd => struct {
        pub const ASYNC = 1;
        pub const INVALIDATE = 2;
        pub const SYNC = 4;
    },
    else => void,
};
pub const MMAP2_UNIT = switch (native_os) {
    .linux => linux.MMAP2_UNIT,
    else => void,
};
pub const NAME_MAX = switch (native_os) {
    .linux => linux.NAME_MAX,
    .emscripten => emscripten.NAME_MAX,
    // Haiku's headers make this 256, to contain room for the terminating null
    // character, but POSIX definition says that NAME_MAX does not include the
    // terminating null.
    .haiku, .openbsd, .dragonfly, .netbsd, .solaris, .illumos, .freebsd, .macos, .ios, .tvos, .watchos, .visionos => 255,
    else => {},
};
pub const PATH_MAX = switch (native_os) {
    .linux => linux.PATH_MAX,
    .emscripten => emscripten.PATH_MAX,
    .wasi => 4096,
    .windows => 260,
    .openbsd, .haiku, .dragonfly, .netbsd, .solaris, .illumos, .freebsd, .macos, .ios, .tvos, .watchos, .visionos => 1024,
    else => {},
};

pub const POLL = switch (native_os) {
    .linux => linux.POLL,
    .emscripten => emscripten.POLL,
    .wasi => struct {
        pub const RDNORM = 0x1;
        pub const WRNORM = 0x2;
        pub const IN = RDNORM;
        pub const OUT = WRNORM;
        pub const ERR = 0x1000;
        pub const HUP = 0x2000;
        pub const NVAL = 0x4000;
    },
    .windows => ws2_32.POLL,
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const IN = 0x001;
        pub const PRI = 0x002;
        pub const OUT = 0x004;
        pub const RDNORM = 0x040;
        pub const WRNORM = OUT;
        pub const RDBAND = 0x080;
        pub const WRBAND = 0x100;

        pub const EXTEND = 0x0200;
        pub const ATTRIB = 0x0400;
        pub const NLINK = 0x0800;
        pub const WRITE = 0x1000;

        pub const ERR = 0x008;
        pub const HUP = 0x010;
        pub const NVAL = 0x020;

        pub const STANDARD = IN | PRI | OUT | RDNORM | RDBAND | WRBAND | ERR | HUP | NVAL;
    },
    .freebsd => struct {
        /// any readable data available.
        pub const IN = 0x0001;
        /// OOB/Urgent readable data.
        pub const PRI = 0x0002;
        /// file descriptor is writeable.
        pub const OUT = 0x0004;
        /// non-OOB/URG data available.
        pub const RDNORM = 0x0040;
        /// no write type differentiation.
        pub const WRNORM = OUT;
        /// OOB/Urgent readable data.
        pub const RDBAND = 0x0080;
        /// OOB/Urgent data can be written.
        pub const WRBAND = 0x0100;
        /// like IN, except ignore EOF.
        pub const INIGNEOF = 0x2000;
        /// some poll error occurred.
        pub const ERR = 0x0008;
        /// file descriptor was "hung up".
        pub const HUP = 0x0010;
        /// requested events "invalid".
        pub const NVAL = 0x0020;

        pub const STANDARD = IN | PRI | OUT | RDNORM | RDBAND | WRBAND | ERR | HUP | NVAL;
    },
    .solaris, .illumos => struct {
        pub const IN = 0x0001;
        pub const PRI = 0x0002;
        pub const OUT = 0x0004;
        pub const RDNORM = 0x0040;
        pub const WRNORM = .OUT;
        pub const RDBAND = 0x0080;
        pub const WRBAND = 0x0100;
        /// Read-side hangup.
        pub const RDHUP = 0x4000;

        /// Non-testable events (may not be specified in events).
        pub const ERR = 0x0008;
        pub const HUP = 0x0010;
        pub const NVAL = 0x0020;

        /// Events to control `/dev/poll` (not specified in revents)
        pub const REMOVE = 0x0800;
        pub const ONESHOT = 0x1000;
        pub const ET = 0x2000;
    },
    .dragonfly, .netbsd => struct {
        /// Testable events (may be specified in events field).
        pub const IN = 0x0001;
        pub const PRI = 0x0002;
        pub const OUT = 0x0004;
        pub const RDNORM = 0x0040;
        pub const WRNORM = OUT;
        pub const RDBAND = 0x0080;
        pub const WRBAND = 0x0100;

        /// Non-testable events (may not be specified in events field).
        pub const ERR = 0x0008;
        pub const HUP = 0x0010;
        pub const NVAL = 0x0020;
    },
    .haiku => struct {
        /// any readable data available
        pub const IN = 0x0001;
        /// file descriptor is writeable
        pub const OUT = 0x0002;
        pub const RDNORM = IN;
        pub const WRNORM = OUT;
        /// priority readable data
        pub const RDBAND = 0x0008;
        /// priority data can be written
        pub const WRBAND = 0x0010;
        /// high priority readable data
        pub const PRI = 0x0020;

        /// errors pending
        pub const ERR = 0x0004;
        /// disconnected
        pub const HUP = 0x0080;
        /// invalid file descriptor
        pub const NVAL = 0x1000;
    },
    .openbsd => struct {
        pub const IN = 0x0001;
        pub const PRI = 0x0002;
        pub const OUT = 0x0004;
        pub const ERR = 0x0008;
        pub const HUP = 0x0010;
        pub const NVAL = 0x0020;
        pub const RDNORM = 0x0040;
        pub const NORM = RDNORM;
        pub const WRNORM = OUT;
        pub const RDBAND = 0x0080;
        pub const WRBAND = 0x0100;
    },
    else => void,
};

/// Basic memory protection flags
pub const PROT = switch (native_os) {
    .linux => linux.PROT,
    .emscripten => emscripten.PROT,
    .openbsd, .haiku, .dragonfly, .netbsd, .solaris, .illumos, .freebsd, .windows => struct {
        /// page can not be accessed
        pub const NONE = 0x0;
        /// page can be read
        pub const READ = 0x1;
        /// page can be written
        pub const WRITE = 0x2;
        /// page can be executed
        pub const EXEC = 0x4;
    },
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        /// [MC2] no permissions
        pub const NONE: vm_prot_t = 0x00;
        /// [MC2] pages can be read
        pub const READ: vm_prot_t = 0x01;
        /// [MC2] pages can be written
        pub const WRITE: vm_prot_t = 0x02;
        /// [MC2] pages can be executed
        pub const EXEC: vm_prot_t = 0x04;
        /// When a caller finds that they cannot obtain write permission on a
        /// mapped entry, the following flag can be used. The entry will be
        /// made "needs copy" effectively copying the object (using COW),
        /// and write permission will be added to the maximum protections for
        /// the associated entry.
        pub const COPY: vm_prot_t = 0x10;
    },
    else => void,
};

pub const REG = switch (native_os) {
    .linux => linux.REG,
    .emscripten => emscripten.REG,
    .freebsd => switch (builtin.cpu.arch) {
        .aarch64 => struct {
            pub const FP = 29;
            pub const SP = 31;
            pub const PC = 32;
        },
        .arm => struct {
            pub const FP = 11;
            pub const SP = 13;
            pub const PC = 15;
        },
        .x86_64 => struct {
            pub const RBP = 12;
            pub const RIP = 21;
            pub const RSP = 24;
        },
        else => struct {},
    },
    .solaris, .illumos => struct {
        pub const R15 = 0;
        pub const R14 = 1;
        pub const R13 = 2;
        pub const R12 = 3;
        pub const R11 = 4;
        pub const R10 = 5;
        pub const R9 = 6;
        pub const R8 = 7;
        pub const RDI = 8;
        pub const RSI = 9;
        pub const RBP = 10;
        pub const RBX = 11;
        pub const RDX = 12;
        pub const RCX = 13;
        pub const RAX = 14;
        pub const RIP = 17;
        pub const RSP = 20;
    },
    .netbsd => switch (builtin.cpu.arch) {
        .aarch64 => struct {
            pub const FP = 29;
            pub const SP = 31;
            pub const PC = 32;
        },
        .arm => struct {
            pub const FP = 11;
            pub const SP = 13;
            pub const PC = 15;
        },
        .x86_64 => struct {
            pub const RDI = 0;
            pub const RSI = 1;
            pub const RDX = 2;
            pub const RCX = 3;
            pub const R8 = 4;
            pub const R9 = 5;
            pub const R10 = 6;
            pub const R11 = 7;
            pub const R12 = 8;
            pub const R13 = 9;
            pub const R14 = 10;
            pub const R15 = 11;
            pub const RBP = 12;
            pub const RBX = 13;
            pub const RAX = 14;
            pub const GS = 15;
            pub const FS = 16;
            pub const ES = 17;
            pub const DS = 18;
            pub const TRAPNO = 19;
            pub const ERR = 20;
            pub const RIP = 21;
            pub const CS = 22;
            pub const RFLAGS = 23;
            pub const RSP = 24;
            pub const SS = 25;
        },
        else => struct {},
    },
    else => struct {},
};
pub const RLIM = switch (native_os) {
    .linux => linux.RLIM,
    .emscripten => emscripten.RLIM,
    .openbsd, .haiku, .dragonfly, .netbsd, .freebsd, .macos, .ios, .tvos, .watchos, .visionos => struct {
        /// No limit
        pub const INFINITY: rlim_t = (1 << 63) - 1;

        pub const SAVED_MAX = INFINITY;
        pub const SAVED_CUR = INFINITY;
    },
    .solaris, .illumos => struct {
        /// No limit
        pub const INFINITY: rlim_t = (1 << 63) - 3;
        pub const SAVED_MAX: rlim_t = (1 << 63) - 2;
        pub const SAVED_CUR: rlim_t = (1 << 63) - 1;
    },
    else => void,
};
pub const S = switch (native_os) {
    .linux => linux.S,
    .emscripten => emscripten.S,
    .wasi => struct {
        pub const IEXEC = @compileError("TODO audit this");
        pub const IFBLK = 0x6000;
        pub const IFCHR = 0x2000;
        pub const IFDIR = 0x4000;
        pub const IFIFO = 0xc000;
        pub const IFLNK = 0xa000;
        pub const IFMT = IFBLK | IFCHR | IFDIR | IFIFO | IFLNK | IFREG | IFSOCK;
        pub const IFREG = 0x8000;
        /// There's no concept of UNIX domain socket but we define this value here
        /// in order to line with other OSes.
        pub const IFSOCK = 0x1;
    },
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const IFMT = 0o170000;

        pub const IFIFO = 0o010000;
        pub const IFCHR = 0o020000;
        pub const IFDIR = 0o040000;
        pub const IFBLK = 0o060000;
        pub const IFREG = 0o100000;
        pub const IFLNK = 0o120000;
        pub const IFSOCK = 0o140000;
        pub const IFWHT = 0o160000;

        pub const ISUID = 0o4000;
        pub const ISGID = 0o2000;
        pub const ISVTX = 0o1000;
        pub const IRWXU = 0o700;
        pub const IRUSR = 0o400;
        pub const IWUSR = 0o200;
        pub const IXUSR = 0o100;
        pub const IRWXG = 0o070;
        pub const IRGRP = 0o040;
        pub const IWGRP = 0o020;
        pub const IXGRP = 0o010;
        pub const IRWXO = 0o007;
        pub const IROTH = 0o004;
        pub const IWOTH = 0o002;
        pub const IXOTH = 0o001;

        pub fn ISFIFO(m: u32) bool {
            return m & IFMT == IFIFO;
        }

        pub fn ISCHR(m: u32) bool {
            return m & IFMT == IFCHR;
        }

        pub fn ISDIR(m: u32) bool {
            return m & IFMT == IFDIR;
        }

        pub fn ISBLK(m: u32) bool {
            return m & IFMT == IFBLK;
        }

        pub fn ISREG(m: u32) bool {
            return m & IFMT == IFREG;
        }

        pub fn ISLNK(m: u32) bool {
            return m & IFMT == IFLNK;
        }

        pub fn ISSOCK(m: u32) bool {
            return m & IFMT == IFSOCK;
        }

        pub fn IWHT(m: u32) bool {
            return m & IFMT == IFWHT;
        }
    },
    .freebsd => struct {
        pub const IFMT = 0o170000;

        pub const IFIFO = 0o010000;
        pub const IFCHR = 0o020000;
        pub const IFDIR = 0o040000;
        pub const IFBLK = 0o060000;
        pub const IFREG = 0o100000;
        pub const IFLNK = 0o120000;
        pub const IFSOCK = 0o140000;
        pub const IFWHT = 0o160000;

        pub const ISUID = 0o4000;
        pub const ISGID = 0o2000;
        pub const ISVTX = 0o1000;
        pub const IRWXU = 0o700;
        pub const IRUSR = 0o400;
        pub const IWUSR = 0o200;
        pub const IXUSR = 0o100;
        pub const IRWXG = 0o070;
        pub const IRGRP = 0o040;
        pub const IWGRP = 0o020;
        pub const IXGRP = 0o010;
        pub const IRWXO = 0o007;
        pub const IROTH = 0o004;
        pub const IWOTH = 0o002;
        pub const IXOTH = 0o001;

        pub fn ISFIFO(m: u32) bool {
            return m & IFMT == IFIFO;
        }

        pub fn ISCHR(m: u32) bool {
            return m & IFMT == IFCHR;
        }

        pub fn ISDIR(m: u32) bool {
            return m & IFMT == IFDIR;
        }

        pub fn ISBLK(m: u32) bool {
            return m & IFMT == IFBLK;
        }

        pub fn ISREG(m: u32) bool {
            return m & IFMT == IFREG;
        }

        pub fn ISLNK(m: u32) bool {
            return m & IFMT == IFLNK;
        }

        pub fn ISSOCK(m: u32) bool {
            return m & IFMT == IFSOCK;
        }

        pub fn IWHT(m: u32) bool {
            return m & IFMT == IFWHT;
        }
    },
    .solaris, .illumos => struct {
        pub const IFMT = 0o170000;

        pub const IFIFO = 0o010000;
        pub const IFCHR = 0o020000;
        pub const IFDIR = 0o040000;
        pub const IFBLK = 0o060000;
        pub const IFREG = 0o100000;
        pub const IFLNK = 0o120000;
        pub const IFSOCK = 0o140000;
        /// SunOS 2.6 Door
        pub const IFDOOR = 0o150000;
        /// Solaris 10 Event Port
        pub const IFPORT = 0o160000;

        pub const ISUID = 0o4000;
        pub const ISGID = 0o2000;
        pub const ISVTX = 0o1000;
        pub const IRWXU = 0o700;
        pub const IRUSR = 0o400;
        pub const IWUSR = 0o200;
        pub const IXUSR = 0o100;
        pub const IRWXG = 0o070;
        pub const IRGRP = 0o040;
        pub const IWGRP = 0o020;
        pub const IXGRP = 0o010;
        pub const IRWXO = 0o007;
        pub const IROTH = 0o004;
        pub const IWOTH = 0o002;
        pub const IXOTH = 0o001;

        pub fn ISFIFO(m: u32) bool {
            return m & IFMT == IFIFO;
        }

        pub fn ISCHR(m: u32) bool {
            return m & IFMT == IFCHR;
        }

        pub fn ISDIR(m: u32) bool {
            return m & IFMT == IFDIR;
        }

        pub fn ISBLK(m: u32) bool {
            return m & IFMT == IFBLK;
        }

        pub fn ISREG(m: u32) bool {
            return m & IFMT == IFREG;
        }

        pub fn ISLNK(m: u32) bool {
            return m & IFMT == IFLNK;
        }

        pub fn ISSOCK(m: u32) bool {
            return m & IFMT == IFSOCK;
        }

        pub fn ISDOOR(m: u32) bool {
            return m & IFMT == IFDOOR;
        }

        pub fn ISPORT(m: u32) bool {
            return m & IFMT == IFPORT;
        }
    },
    .netbsd => struct {
        pub const IFMT = 0o170000;

        pub const IFIFO = 0o010000;
        pub const IFCHR = 0o020000;
        pub const IFDIR = 0o040000;
        pub const IFBLK = 0o060000;
        pub const IFREG = 0o100000;
        pub const IFLNK = 0o120000;
        pub const IFSOCK = 0o140000;
        pub const IFWHT = 0o160000;

        pub const ISUID = 0o4000;
        pub const ISGID = 0o2000;
        pub const ISVTX = 0o1000;
        pub const IRWXU = 0o700;
        pub const IRUSR = 0o400;
        pub const IWUSR = 0o200;
        pub const IXUSR = 0o100;
        pub const IRWXG = 0o070;
        pub const IRGRP = 0o040;
        pub const IWGRP = 0o020;
        pub const IXGRP = 0o010;
        pub const IRWXO = 0o007;
        pub const IROTH = 0o004;
        pub const IWOTH = 0o002;
        pub const IXOTH = 0o001;

        pub fn ISFIFO(m: u32) bool {
            return m & IFMT == IFIFO;
        }

        pub fn ISCHR(m: u32) bool {
            return m & IFMT == IFCHR;
        }

        pub fn ISDIR(m: u32) bool {
            return m & IFMT == IFDIR;
        }

        pub fn ISBLK(m: u32) bool {
            return m & IFMT == IFBLK;
        }

        pub fn ISREG(m: u32) bool {
            return m & IFMT == IFREG;
        }

        pub fn ISLNK(m: u32) bool {
            return m & IFMT == IFLNK;
        }

        pub fn ISSOCK(m: u32) bool {
            return m & IFMT == IFSOCK;
        }

        pub fn IWHT(m: u32) bool {
            return m & IFMT == IFWHT;
        }
    },
    .dragonfly => struct {
        pub const IREAD = IRUSR;
        pub const IEXEC = IXUSR;
        pub const IWRITE = IWUSR;
        pub const IXOTH = 1;
        pub const IWOTH = 2;
        pub const IROTH = 4;
        pub const IRWXO = 7;
        pub const IXGRP = 8;
        pub const IWGRP = 16;
        pub const IRGRP = 32;
        pub const IRWXG = 56;
        pub const IXUSR = 64;
        pub const IWUSR = 128;
        pub const IRUSR = 256;
        pub const IRWXU = 448;
        pub const ISTXT = 512;
        pub const BLKSIZE = 512;
        pub const ISVTX = 512;
        pub const ISGID = 1024;
        pub const ISUID = 2048;
        pub const IFIFO = 4096;
        pub const IFCHR = 8192;
        pub const IFDIR = 16384;
        pub const IFBLK = 24576;
        pub const IFREG = 32768;
        pub const IFDB = 36864;
        pub const IFLNK = 40960;
        pub const IFSOCK = 49152;
        pub const IFWHT = 57344;
        pub const IFMT = 61440;

        pub fn ISCHR(m: u32) bool {
            return m & IFMT == IFCHR;
        }
    },
    .haiku => struct {
        pub const IFMT = 0o170000;
        pub const IFSOCK = 0o140000;
        pub const IFLNK = 0o120000;
        pub const IFREG = 0o100000;
        pub const IFBLK = 0o060000;
        pub const IFDIR = 0o040000;
        pub const IFCHR = 0o020000;
        pub const IFIFO = 0o010000;
        pub const INDEX_DIR = 0o4000000000;

        pub const IUMSK = 0o7777;
        pub const ISUID = 0o4000;
        pub const ISGID = 0o2000;
        pub const ISVTX = 0o1000;
        pub const IRWXU = 0o700;
        pub const IRUSR = 0o400;
        pub const IWUSR = 0o200;
        pub const IXUSR = 0o100;
        pub const IRWXG = 0o070;
        pub const IRGRP = 0o040;
        pub const IWGRP = 0o020;
        pub const IXGRP = 0o010;
        pub const IRWXO = 0o007;
        pub const IROTH = 0o004;
        pub const IWOTH = 0o002;
        pub const IXOTH = 0o001;

        pub fn ISREG(m: u32) bool {
            return m & IFMT == IFREG;
        }

        pub fn ISLNK(m: u32) bool {
            return m & IFMT == IFLNK;
        }

        pub fn ISBLK(m: u32) bool {
            return m & IFMT == IFBLK;
        }

        pub fn ISDIR(m: u32) bool {
            return m & IFMT == IFDIR;
        }

        pub fn ISCHR(m: u32) bool {
            return m & IFMT == IFCHR;
        }

        pub fn ISFIFO(m: u32) bool {
            return m & IFMT == IFIFO;
        }

        pub fn ISSOCK(m: u32) bool {
            return m & IFMT == IFSOCK;
        }

        pub fn ISINDEX(m: u32) bool {
            return m & INDEX_DIR == INDEX_DIR;
        }
    },
    .openbsd => struct {
        pub const IFMT = 0o170000;

        pub const IFIFO = 0o010000;
        pub const IFCHR = 0o020000;
        pub const IFDIR = 0o040000;
        pub const IFBLK = 0o060000;
        pub const IFREG = 0o100000;
        pub const IFLNK = 0o120000;
        pub const IFSOCK = 0o140000;

        pub const ISUID = 0o4000;
        pub const ISGID = 0o2000;
        pub const ISVTX = 0o1000;
        pub const IRWXU = 0o700;
        pub const IRUSR = 0o400;
        pub const IWUSR = 0o200;
        pub const IXUSR = 0o100;
        pub const IRWXG = 0o070;
        pub const IRGRP = 0o040;
        pub const IWGRP = 0o020;
        pub const IXGRP = 0o010;
        pub const IRWXO = 0o007;
        pub const IROTH = 0o004;
        pub const IWOTH = 0o002;
        pub const IXOTH = 0o001;

        pub fn ISFIFO(m: u32) bool {
            return m & IFMT == IFIFO;
        }

        pub fn ISCHR(m: u32) bool {
            return m & IFMT == IFCHR;
        }

        pub fn ISDIR(m: u32) bool {
            return m & IFMT == IFDIR;
        }

        pub fn ISBLK(m: u32) bool {
            return m & IFMT == IFBLK;
        }

        pub fn ISREG(m: u32) bool {
            return m & IFMT == IFREG;
        }

        pub fn ISLNK(m: u32) bool {
            return m & IFMT == IFLNK;
        }

        pub fn ISSOCK(m: u32) bool {
            return m & IFMT == IFSOCK;
        }
    },
    else => void,
};
pub const SA = switch (native_os) {
    .linux => linux.SA,
    .emscripten => emscripten.SA,
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        /// take signal on signal stack
        pub const ONSTACK = 0x0001;
        /// restart system on signal return
        pub const RESTART = 0x0002;
        /// reset to SIG.DFL when taking signal
        pub const RESETHAND = 0x0004;
        /// do not generate SIG.CHLD on child stop
        pub const NOCLDSTOP = 0x0008;
        /// don't mask the signal we're delivering
        pub const NODEFER = 0x0010;
        /// don't keep zombies around
        pub const NOCLDWAIT = 0x0020;
        /// signal handler with SIGINFO args
        pub const SIGINFO = 0x0040;
        /// do not bounce off kernel's sigtramp
        pub const USERTRAMP = 0x0100;
        /// signal handler with SIGINFO args with 64bit regs information
        pub const @"64REGSET" = 0x0200;
    },
    .freebsd => struct {
        pub const ONSTACK = 0x0001;
        pub const RESTART = 0x0002;
        pub const RESETHAND = 0x0004;
        pub const NOCLDSTOP = 0x0008;
        pub const NODEFER = 0x0010;
        pub const NOCLDWAIT = 0x0020;
        pub const SIGINFO = 0x0040;
    },
    .solaris, .illumos => struct {
        pub const ONSTACK = 0x00000001;
        pub const RESETHAND = 0x00000002;
        pub const RESTART = 0x00000004;
        pub const SIGINFO = 0x00000008;
        pub const NODEFER = 0x00000010;
        pub const NOCLDWAIT = 0x00010000;
    },
    .netbsd => struct {
        pub const ONSTACK = 0x0001;
        pub const RESTART = 0x0002;
        pub const RESETHAND = 0x0004;
        pub const NOCLDSTOP = 0x0008;
        pub const NODEFER = 0x0010;
        pub const NOCLDWAIT = 0x0020;
        pub const SIGINFO = 0x0040;
    },
    .dragonfly => struct {
        pub const ONSTACK = 0x0001;
        pub const RESTART = 0x0002;
        pub const RESETHAND = 0x0004;
        pub const NODEFER = 0x0010;
        pub const NOCLDWAIT = 0x0020;
        pub const SIGINFO = 0x0040;
    },
    .haiku => struct {
        pub const NOCLDSTOP = 0x01;
        pub const NOCLDWAIT = 0x02;
        pub const RESETHAND = 0x04;
        pub const NODEFER = 0x08;
        pub const RESTART = 0x10;
        pub const ONSTACK = 0x20;
        pub const SIGINFO = 0x40;
        pub const NOMASK = NODEFER;
        pub const STACK = ONSTACK;
        pub const ONESHOT = RESETHAND;
    },
    .openbsd => struct {
        pub const ONSTACK = 0x0001;
        pub const RESTART = 0x0002;
        pub const RESETHAND = 0x0004;
        pub const NOCLDSTOP = 0x0008;
        pub const NODEFER = 0x0010;
        pub const NOCLDWAIT = 0x0020;
        pub const SIGINFO = 0x0040;
    },
    else => void,
};
pub const sigval_t = switch (native_os) {
    .netbsd, .solaris, .illumos => extern union {
        int: i32,
        ptr: ?*anyopaque,
    },
    else => void,
};

pub const SC = switch (native_os) {
    .linux => linux.SC,
    else => void,
};
pub const SEEK = switch (native_os) {
    .linux => linux.SEEK,
    .emscripten => emscripten.SEEK,
    .wasi => struct {
        pub const SET: wasi.whence_t = .SET;
        pub const CUR: wasi.whence_t = .CUR;
        pub const END: wasi.whence_t = .END;
    },
    .openbsd, .haiku, .netbsd, .freebsd, .macos, .ios, .tvos, .watchos, .visionos, .windows => struct {
        pub const SET = 0;
        pub const CUR = 1;
        pub const END = 2;
    },
    .dragonfly, .solaris, .illumos => struct {
        pub const SET = 0;
        pub const CUR = 1;
        pub const END = 2;
        pub const DATA = 3;
        pub const HOLE = 4;
    },
    else => void,
};
pub const SHUT = switch (native_os) {
    .linux => linux.SHUT,
    .emscripten => emscripten.SHUT,
    else => struct {
        pub const RD = 0;
        pub const WR = 1;
        pub const RDWR = 2;
    },
};

/// Signal types
pub const SIG = switch (native_os) {
    .linux => linux.SIG,
    .emscripten => emscripten.SIG,
    .windows => struct {
        /// interrupt
        pub const INT = 2;
        /// illegal instruction - invalid function image
        pub const ILL = 4;
        /// floating point exception
        pub const FPE = 8;
        /// segment violation
        pub const SEGV = 11;
        /// Software termination signal from kill
        pub const TERM = 15;
        /// Ctrl-Break sequence
        pub const BREAK = 21;
        /// abnormal termination triggered by abort call
        pub const ABRT = 22;
        /// SIGABRT compatible with other platforms, same as SIGABRT
        pub const ABRT_COMPAT = 6;

        // Signal action codes
        /// default signal action
        pub const DFL = 0;
        /// ignore signal
        pub const IGN = 1;
        /// return current value
        pub const GET = 2;
        /// signal gets error
        pub const SGE = 3;
        /// acknowledge
        pub const ACK = 4;
        /// Signal error value (returned by signal call on error)
        pub const ERR = -1;
    },
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const ERR: ?Sigaction.handler_fn = @ptrFromInt(maxInt(usize));
        pub const DFL: ?Sigaction.handler_fn = @ptrFromInt(0);
        pub const IGN: ?Sigaction.handler_fn = @ptrFromInt(1);
        pub const HOLD: ?Sigaction.handler_fn = @ptrFromInt(5);

        /// block specified signal set
        pub const BLOCK = 1;
        /// unblock specified signal set
        pub const UNBLOCK = 2;
        /// set specified signal set
        pub const SETMASK = 3;
        /// hangup
        pub const HUP = 1;
        /// interrupt
        pub const INT = 2;
        /// quit
        pub const QUIT = 3;
        /// illegal instruction (not reset when caught)
        pub const ILL = 4;
        /// trace trap (not reset when caught)
        pub const TRAP = 5;
        /// abort()
        pub const ABRT = 6;
        /// pollable event ([XSR] generated, not supported)
        pub const POLL = 7;
        /// compatibility
        pub const IOT = ABRT;
        /// EMT instruction
        pub const EMT = 7;
        /// floating point exception
        pub const FPE = 8;
        /// kill (cannot be caught or ignored)
        pub const KILL = 9;
        /// bus error
        pub const BUS = 10;
        /// segmentation violation
        pub const SEGV = 11;
        /// bad argument to system call
        pub const SYS = 12;
        /// write on a pipe with no one to read it
        pub const PIPE = 13;
        /// alarm clock
        pub const ALRM = 14;
        /// software termination signal from kill
        pub const TERM = 15;
        /// urgent condition on IO channel
        pub const URG = 16;
        /// sendable stop signal not from tty
        pub const STOP = 17;
        /// stop signal from tty
        pub const TSTP = 18;
        /// continue a stopped process
        pub const CONT = 19;
        /// to parent on child stop or exit
        pub const CHLD = 20;
        /// to readers pgrp upon background tty read
        pub const TTIN = 21;
        /// like TTIN for output if (tp->t_local&LTOSTOP)
        pub const TTOU = 22;
        /// input/output possible signal
        pub const IO = 23;
        /// exceeded CPU time limit
        pub const XCPU = 24;
        /// exceeded file size limit
        pub const XFSZ = 25;
        /// virtual time alarm
        pub const VTALRM = 26;
        /// profiling time alarm
        pub const PROF = 27;
        /// window size changes
        pub const WINCH = 28;
        /// information request
        pub const INFO = 29;
        /// user defined signal 1
        pub const USR1 = 30;
        /// user defined signal 2
        pub const USR2 = 31;
    },
    .freebsd => struct {
        pub const HUP = 1;
        pub const INT = 2;
        pub const QUIT = 3;
        pub const ILL = 4;
        pub const TRAP = 5;
        pub const ABRT = 6;
        pub const IOT = ABRT;
        pub const EMT = 7;
        pub const FPE = 8;
        pub const KILL = 9;
        pub const BUS = 10;
        pub const SEGV = 11;
        pub const SYS = 12;
        pub const PIPE = 13;
        pub const ALRM = 14;
        pub const TERM = 15;
        pub const URG = 16;
        pub const STOP = 17;
        pub const TSTP = 18;
        pub const CONT = 19;
        pub const CHLD = 20;
        pub const TTIN = 21;
        pub const TTOU = 22;
        pub const IO = 23;
        pub const XCPU = 24;
        pub const XFSZ = 25;
        pub const VTALRM = 26;
        pub const PROF = 27;
        pub const WINCH = 28;
        pub const INFO = 29;
        pub const USR1 = 30;
        pub const USR2 = 31;
        pub const THR = 32;
        pub const LWP = THR;
        pub const LIBRT = 33;

        pub const RTMIN = 65;
        pub const RTMAX = 126;

        pub const BLOCK = 1;
        pub const UNBLOCK = 2;
        pub const SETMASK = 3;

        pub const DFL: ?Sigaction.handler_fn = @ptrFromInt(0);
        pub const IGN: ?Sigaction.handler_fn = @ptrFromInt(1);
        pub const ERR: ?Sigaction.handler_fn = @ptrFromInt(maxInt(usize));

        pub const WORDS = 4;
        pub const MAXSIG = 128;

        pub inline fn IDX(sig: usize) usize {
            return sig - 1;
        }
        pub inline fn WORD(sig: usize) usize {
            return IDX(sig) >> 5;
        }
        pub inline fn BIT(sig: usize) usize {
            return 1 << (IDX(sig) & 31);
        }
        pub inline fn VALID(sig: usize) usize {
            return sig <= MAXSIG and sig > 0;
        }
    },
    .solaris, .illumos => struct {
        pub const DFL: ?Sigaction.handler_fn = @ptrFromInt(0);
        pub const ERR: ?Sigaction.handler_fn = @ptrFromInt(maxInt(usize));
        pub const IGN: ?Sigaction.handler_fn = @ptrFromInt(1);
        pub const HOLD: ?Sigaction.handler_fn = @ptrFromInt(2);

        pub const WORDS = 4;
        pub const MAXSIG = 75;

        pub const SIG_BLOCK = 1;
        pub const SIG_UNBLOCK = 2;
        pub const SIG_SETMASK = 3;

        pub const HUP = 1;
        pub const INT = 2;
        pub const QUIT = 3;
        pub const ILL = 4;
        pub const TRAP = 5;
        pub const IOT = 6;
        pub const ABRT = 6;
        pub const EMT = 7;
        pub const FPE = 8;
        pub const KILL = 9;
        pub const BUS = 10;
        pub const SEGV = 11;
        pub const SYS = 12;
        pub const PIPE = 13;
        pub const ALRM = 14;
        pub const TERM = 15;
        pub const USR1 = 16;
        pub const USR2 = 17;
        pub const CLD = 18;
        pub const CHLD = 18;
        pub const PWR = 19;
        pub const WINCH = 20;
        pub const URG = 21;
        pub const POLL = 22;
        pub const IO = .POLL;
        pub const STOP = 23;
        pub const TSTP = 24;
        pub const CONT = 25;
        pub const TTIN = 26;
        pub const TTOU = 27;
        pub const VTALRM = 28;
        pub const PROF = 29;
        pub const XCPU = 30;
        pub const XFSZ = 31;
        pub const WAITING = 32;
        pub const LWP = 33;
        pub const FREEZE = 34;
        pub const THAW = 35;
        pub const CANCEL = 36;
        pub const LOST = 37;
        pub const XRES = 38;
        pub const JVM1 = 39;
        pub const JVM2 = 40;
        pub const INFO = 41;

        pub const RTMIN = 42;
        pub const RTMAX = 74;

        pub inline fn IDX(sig: usize) usize {
            return sig - 1;
        }
        pub inline fn WORD(sig: usize) usize {
            return IDX(sig) >> 5;
        }
        pub inline fn BIT(sig: usize) usize {
            return 1 << (IDX(sig) & 31);
        }
        pub inline fn VALID(sig: usize) usize {
            return sig <= MAXSIG and sig > 0;
        }
    },
    .netbsd => struct {
        pub const DFL: ?Sigaction.handler_fn = @ptrFromInt(0);
        pub const IGN: ?Sigaction.handler_fn = @ptrFromInt(1);
        pub const ERR: ?Sigaction.handler_fn = @ptrFromInt(maxInt(usize));

        pub const WORDS = 4;
        pub const MAXSIG = 128;

        pub const BLOCK = 1;
        pub const UNBLOCK = 2;
        pub const SETMASK = 3;

        pub const HUP = 1;
        pub const INT = 2;
        pub const QUIT = 3;
        pub const ILL = 4;
        pub const TRAP = 5;
        pub const ABRT = 6;
        pub const IOT = ABRT;
        pub const EMT = 7;
        pub const FPE = 8;
        pub const KILL = 9;
        pub const BUS = 10;
        pub const SEGV = 11;
        pub const SYS = 12;
        pub const PIPE = 13;
        pub const ALRM = 14;
        pub const TERM = 15;
        pub const URG = 16;
        pub const STOP = 17;
        pub const TSTP = 18;
        pub const CONT = 19;
        pub const CHLD = 20;
        pub const TTIN = 21;
        pub const TTOU = 22;
        pub const IO = 23;
        pub const XCPU = 24;
        pub const XFSZ = 25;
        pub const VTALRM = 26;
        pub const PROF = 27;
        pub const WINCH = 28;
        pub const INFO = 29;
        pub const USR1 = 30;
        pub const USR2 = 31;
        pub const PWR = 32;

        pub const RTMIN = 33;
        pub const RTMAX = 63;

        pub inline fn IDX(sig: usize) usize {
            return sig - 1;
        }
        pub inline fn WORD(sig: usize) usize {
            return IDX(sig) >> 5;
        }
        pub inline fn BIT(sig: usize) usize {
            return 1 << (IDX(sig) & 31);
        }
        pub inline fn VALID(sig: usize) usize {
            return sig <= MAXSIG and sig > 0;
        }
    },
    .dragonfly => struct {
        pub const DFL: ?Sigaction.handler_fn = @ptrFromInt(0);
        pub const IGN: ?Sigaction.handler_fn = @ptrFromInt(1);
        pub const ERR: ?Sigaction.handler_fn = @ptrFromInt(maxInt(usize));

        pub const BLOCK = 1;
        pub const UNBLOCK = 2;
        pub const SETMASK = 3;

        pub const IOT = ABRT;
        pub const HUP = 1;
        pub const INT = 2;
        pub const QUIT = 3;
        pub const ILL = 4;
        pub const TRAP = 5;
        pub const ABRT = 6;
        pub const EMT = 7;
        pub const FPE = 8;
        pub const KILL = 9;
        pub const BUS = 10;
        pub const SEGV = 11;
        pub const SYS = 12;
        pub const PIPE = 13;
        pub const ALRM = 14;
        pub const TERM = 15;
        pub const URG = 16;
        pub const STOP = 17;
        pub const TSTP = 18;
        pub const CONT = 19;
        pub const CHLD = 20;
        pub const TTIN = 21;
        pub const TTOU = 22;
        pub const IO = 23;
        pub const XCPU = 24;
        pub const XFSZ = 25;
        pub const VTALRM = 26;
        pub const PROF = 27;
        pub const WINCH = 28;
        pub const INFO = 29;
        pub const USR1 = 30;
        pub const USR2 = 31;
        pub const THR = 32;
        pub const CKPT = 33;
        pub const CKPTEXIT = 34;

        pub const WORDS = 4;
    },
    .haiku => struct {
        pub const DFL: ?Sigaction.handler_fn = @ptrFromInt(0);
        pub const IGN: ?Sigaction.handler_fn = @ptrFromInt(1);
        pub const ERR: ?Sigaction.handler_fn = @ptrFromInt(maxInt(usize));

        pub const HOLD: ?Sigaction.handler_fn = @ptrFromInt(3);

        pub const HUP = 1;
        pub const INT = 2;
        pub const QUIT = 3;
        pub const ILL = 4;
        pub const CHLD = 5;
        pub const ABRT = 6;
        pub const IOT = ABRT;
        pub const PIPE = 7;
        pub const FPE = 8;
        pub const KILL = 9;
        pub const STOP = 10;
        pub const SEGV = 11;
        pub const CONT = 12;
        pub const TSTP = 13;
        pub const ALRM = 14;
        pub const TERM = 15;
        pub const TTIN = 16;
        pub const TTOU = 17;
        pub const USR1 = 18;
        pub const USR2 = 19;
        pub const WINCH = 20;
        pub const KILLTHR = 21;
        pub const TRAP = 22;
        pub const POLL = 23;
        pub const PROF = 24;
        pub const SYS = 25;
        pub const URG = 26;
        pub const VTALRM = 27;
        pub const XCPU = 28;
        pub const XFSZ = 29;
        pub const BUS = 30;
        pub const RESERVED1 = 31;
        pub const RESERVED2 = 32;

        pub const BLOCK = 1;
        pub const UNBLOCK = 2;
        pub const SETMASK = 3;
    },
    .openbsd => struct {
        pub const DFL: ?Sigaction.handler_fn = @ptrFromInt(0);
        pub const IGN: ?Sigaction.handler_fn = @ptrFromInt(1);
        pub const ERR: ?Sigaction.handler_fn = @ptrFromInt(maxInt(usize));
        pub const CATCH: ?Sigaction.handler_fn = @ptrFromInt(2);
        pub const HOLD: ?Sigaction.handler_fn = @ptrFromInt(3);

        pub const HUP = 1;
        pub const INT = 2;
        pub const QUIT = 3;
        pub const ILL = 4;
        pub const TRAP = 5;
        pub const ABRT = 6;
        pub const IOT = ABRT;
        pub const EMT = 7;
        pub const FPE = 8;
        pub const KILL = 9;
        pub const BUS = 10;
        pub const SEGV = 11;
        pub const SYS = 12;
        pub const PIPE = 13;
        pub const ALRM = 14;
        pub const TERM = 15;
        pub const URG = 16;
        pub const STOP = 17;
        pub const TSTP = 18;
        pub const CONT = 19;
        pub const CHLD = 20;
        pub const TTIN = 21;
        pub const TTOU = 22;
        pub const IO = 23;
        pub const XCPU = 24;
        pub const XFSZ = 25;
        pub const VTALRM = 26;
        pub const PROF = 27;
        pub const WINCH = 28;
        pub const INFO = 29;
        pub const USR1 = 30;
        pub const USR2 = 31;
        pub const PWR = 32;

        pub const BLOCK = 1;
        pub const UNBLOCK = 2;
        pub const SETMASK = 3;
    },
    else => void,
};

pub const SIOCGIFINDEX = switch (native_os) {
    .linux => linux.SIOCGIFINDEX,
    .emscripten => emscripten.SIOCGIFINDEX,
    .solaris, .illumos => solaris.SIOCGLIFINDEX,
    else => void,
};

pub const STDIN_FILENO = switch (native_os) {
    .linux => linux.STDIN_FILENO,
    .emscripten => emscripten.STDIN_FILENO,
    else => 0,
};
pub const STDOUT_FILENO = switch (native_os) {
    .linux => linux.STDOUT_FILENO,
    .emscripten => emscripten.STDOUT_FILENO,
    else => 1,
};
pub const STDERR_FILENO = switch (native_os) {
    .linux => linux.STDERR_FILENO,
    .emscripten => emscripten.STDERR_FILENO,
    else => 2,
};

pub const SYS = switch (native_os) {
    .linux => linux.SYS,
    else => void,
};
/// Renamed from `sigaction` to `Sigaction` to avoid conflict with function name.
pub const Sigaction = switch (native_os) {
    .linux => switch (native_arch) {
        .mips,
        .mipsel,
        .mips64,
        .mips64el,
        => if (builtin.target.isMusl())
            linux.Sigaction
        else if (builtin.target.ptrBitWidth() == 64) extern struct {
            pub const handler_fn = *align(1) const fn (i32) callconv(.C) void;
            pub const sigaction_fn = *const fn (i32, *const siginfo_t, ?*anyopaque) callconv(.C) void;

            flags: c_uint,
            handler: extern union {
                handler: ?handler_fn,
                sigaction: ?sigaction_fn,
            },
            mask: sigset_t,
            restorer: ?*const fn () callconv(.C) void = null,
        } else extern struct {
            pub const handler_fn = *align(1) const fn (i32) callconv(.C) void;
            pub const sigaction_fn = *const fn (i32, *const siginfo_t, ?*anyopaque) callconv(.C) void;

            flags: c_uint,
            handler: extern union {
                handler: ?handler_fn,
                sigaction: ?sigaction_fn,
            },
            mask: sigset_t,
            restorer: ?*const fn () callconv(.C) void = null,
            __resv: [1]c_int = .{0},
        },
        .s390x => if (builtin.abi == .gnu) extern struct {
            pub const handler_fn = *align(1) const fn (i32) callconv(.C) void;
            pub const sigaction_fn = *const fn (i32, *const siginfo_t, ?*anyopaque) callconv(.C) void;

            handler: extern union {
                handler: ?handler_fn,
                sigaction: ?sigaction_fn,
            },
            __glibc_reserved0: c_int = 0,
            flags: c_uint,
            restorer: ?*const fn () callconv(.C) void = null,
            mask: sigset_t,
        } else linux.Sigaction,
        else => linux.Sigaction,
    },
    .emscripten => emscripten.Sigaction,
    .netbsd, .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        pub const handler_fn = *align(1) const fn (i32) callconv(.C) void;
        pub const sigaction_fn = *const fn (i32, *const siginfo_t, ?*anyopaque) callconv(.C) void;

        handler: extern union {
            handler: ?handler_fn,
            sigaction: ?sigaction_fn,
        },
        mask: sigset_t,
        flags: c_uint,
    },
    .dragonfly, .freebsd => extern struct {
        pub const handler_fn = *align(1) const fn (i32) callconv(.C) void;
        pub const sigaction_fn = *const fn (i32, *const siginfo_t, ?*anyopaque) callconv(.C) void;

        /// signal handler
        handler: extern union {
            handler: ?handler_fn,
            sigaction: ?sigaction_fn,
        },
        /// see signal options
        flags: c_uint,
        /// signal mask to apply
        mask: sigset_t,
    },
    .solaris, .illumos => extern struct {
        pub const handler_fn = *align(1) const fn (i32) callconv(.C) void;
        pub const sigaction_fn = *const fn (i32, *const siginfo_t, ?*anyopaque) callconv(.C) void;

        /// signal options
        flags: c_uint,
        /// signal handler
        handler: extern union {
            handler: ?handler_fn,
            sigaction: ?sigaction_fn,
        },
        /// signal mask to apply
        mask: sigset_t,
    },
    .haiku => extern struct {
        pub const handler_fn = *align(1) const fn (i32) callconv(.C) void;
        pub const sigaction_fn = *const fn (i32, *const siginfo_t, ?*anyopaque) callconv(.C) void;

        /// signal handler
        handler: extern union {
            handler: handler_fn,
            sigaction: sigaction_fn,
        },

        /// signal mask to apply
        mask: sigset_t,

        /// see signal options
        flags: i32,

        /// will be passed to the signal handler, BeOS extension
        userdata: *allowzero anyopaque = undefined,
    },
    .openbsd => extern struct {
        pub const handler_fn = *align(1) const fn (i32) callconv(.C) void;
        pub const sigaction_fn = *const fn (i32, *const siginfo_t, ?*anyopaque) callconv(.C) void;

        /// signal handler
        handler: extern union {
            handler: ?handler_fn,
            sigaction: ?sigaction_fn,
        },
        /// signal mask to apply
        mask: sigset_t,
        /// signal options
        flags: c_uint,
    },
    else => void,
};
pub const T = switch (native_os) {
    .linux => linux.T,
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const IOCGWINSZ = ior(0x40000000, 't', 104, @sizeOf(winsize));

        fn ior(inout: u32, group: usize, num: usize, len: usize) usize {
            return (inout | ((len & IOCPARM_MASK) << 16) | ((group) << 8) | (num));
        }
    },
    .freebsd => struct {
        pub const IOCEXCL = 0x2000740d;
        pub const IOCNXCL = 0x2000740e;
        pub const IOCSCTTY = 0x20007461;
        pub const IOCGPGRP = 0x40047477;
        pub const IOCSPGRP = 0x80047476;
        pub const IOCOUTQ = 0x40047473;
        pub const IOCSTI = 0x80017472;
        pub const IOCGWINSZ = 0x40087468;
        pub const IOCSWINSZ = 0x80087467;
        pub const IOCMGET = 0x4004746a;
        pub const IOCMBIS = 0x8004746c;
        pub const IOCMBIC = 0x8004746b;
        pub const IOCMSET = 0x8004746d;
        pub const FIONREAD = 0x4004667f;
        pub const IOCCONS = 0x80047462;
        pub const IOCPKT = 0x80047470;
        pub const FIONBIO = 0x8004667e;
        pub const IOCNOTTY = 0x20007471;
        pub const IOCSETD = 0x8004741b;
        pub const IOCGETD = 0x4004741a;
        pub const IOCSBRK = 0x2000747b;
        pub const IOCCBRK = 0x2000747a;
        pub const IOCGSID = 0x40047463;
        pub const IOCGPTN = 0x4004740f;
        pub const IOCSIG = 0x2004745f;
    },
    .solaris, .illumos => struct {
        pub const CGETA = tioc('T', 1);
        pub const CSETA = tioc('T', 2);
        pub const CSETAW = tioc('T', 3);
        pub const CSETAF = tioc('T', 4);
        pub const CSBRK = tioc('T', 5);
        pub const CXONC = tioc('T', 6);
        pub const CFLSH = tioc('T', 7);
        pub const IOCGWINSZ = tioc('T', 104);
        pub const IOCSWINSZ = tioc('T', 103);
        // Softcarrier ioctls
        pub const IOCGSOFTCAR = tioc('T', 105);
        pub const IOCSSOFTCAR = tioc('T', 106);
        // termios ioctls
        pub const CGETS = tioc('T', 13);
        pub const CSETS = tioc('T', 14);
        pub const CSANOW = tioc('T', 14);
        pub const CSETSW = tioc('T', 15);
        pub const CSADRAIN = tioc('T', 15);
        pub const CSETSF = tioc('T', 16);
        pub const IOCSETLD = tioc('T', 123);
        pub const IOCGETLD = tioc('T', 124);
        // NTP PPS ioctls
        pub const IOCGPPS = tioc('T', 125);
        pub const IOCSPPS = tioc('T', 126);
        pub const IOCGPPSEV = tioc('T', 127);

        pub const IOCGETD = tioc('t', 0);
        pub const IOCSETD = tioc('t', 1);
        pub const IOCHPCL = tioc('t', 2);
        pub const IOCGETP = tioc('t', 8);
        pub const IOCSETP = tioc('t', 9);
        pub const IOCSETN = tioc('t', 10);
        pub const IOCEXCL = tioc('t', 13);
        pub const IOCNXCL = tioc('t', 14);
        pub const IOCFLUSH = tioc('t', 16);
        pub const IOCSETC = tioc('t', 17);
        pub const IOCGETC = tioc('t', 18);
        /// bis local mode bits
        pub const IOCLBIS = tioc('t', 127);
        /// bic local mode bits
        pub const IOCLBIC = tioc('t', 126);
        /// set entire local mode word
        pub const IOCLSET = tioc('t', 125);
        /// get local modes
        pub const IOCLGET = tioc('t', 124);
        /// set break bit
        pub const IOCSBRK = tioc('t', 123);
        /// clear break bit
        pub const IOCCBRK = tioc('t', 122);
        /// set data terminal ready
        pub const IOCSDTR = tioc('t', 121);
        /// clear data terminal ready
        pub const IOCCDTR = tioc('t', 120);
        /// set local special chars
        pub const IOCSLTC = tioc('t', 117);
        /// get local special chars
        pub const IOCGLTC = tioc('t', 116);
        /// driver output queue size
        pub const IOCOUTQ = tioc('t', 115);
        /// void tty association
        pub const IOCNOTTY = tioc('t', 113);
        /// get a ctty
        pub const IOCSCTTY = tioc('t', 132);
        /// stop output, like ^S
        pub const IOCSTOP = tioc('t', 111);
        /// start output, like ^Q
        pub const IOCSTART = tioc('t', 110);
        /// get pgrp of tty
        pub const IOCGPGRP = tioc('t', 20);
        /// set pgrp of tty
        pub const IOCSPGRP = tioc('t', 21);
        /// get session id on ctty
        pub const IOCGSID = tioc('t', 22);
        /// simulate terminal input
        pub const IOCSTI = tioc('t', 23);
        /// set all modem bits
        pub const IOCMSET = tioc('t', 26);
        /// bis modem bits
        pub const IOCMBIS = tioc('t', 27);
        /// bic modem bits
        pub const IOCMBIC = tioc('t', 28);
        /// get all modem bits
        pub const IOCMGET = tioc('t', 29);

        fn tioc(t: u16, num: u8) u16 {
            return (t << 8) | num;
        }
    },
    .netbsd => struct {
        pub const IOCCBRK = 0x2000747a;
        pub const IOCCDTR = 0x20007478;
        pub const IOCCONS = 0x80047462;
        pub const IOCDCDTIMESTAMP = 0x40107458;
        pub const IOCDRAIN = 0x2000745e;
        pub const IOCEXCL = 0x2000740d;
        pub const IOCEXT = 0x80047460;
        pub const IOCFLAG_CDTRCTS = 0x10;
        pub const IOCFLAG_CLOCAL = 0x2;
        pub const IOCFLAG_CRTSCTS = 0x4;
        pub const IOCFLAG_MDMBUF = 0x8;
        pub const IOCFLAG_SOFTCAR = 0x1;
        pub const IOCFLUSH = 0x80047410;
        pub const IOCGETA = 0x402c7413;
        pub const IOCGETD = 0x4004741a;
        pub const IOCGFLAGS = 0x4004745d;
        pub const IOCGLINED = 0x40207442;
        pub const IOCGPGRP = 0x40047477;
        pub const IOCGQSIZE = 0x40047481;
        pub const IOCGRANTPT = 0x20007447;
        pub const IOCGSID = 0x40047463;
        pub const IOCGSIZE = 0x40087468;
        pub const IOCGWINSZ = 0x40087468;
        pub const IOCMBIC = 0x8004746b;
        pub const IOCMBIS = 0x8004746c;
        pub const IOCMGET = 0x4004746a;
        pub const IOCMSET = 0x8004746d;
        pub const IOCM_CAR = 0x40;
        pub const IOCM_CD = 0x40;
        pub const IOCM_CTS = 0x20;
        pub const IOCM_DSR = 0x100;
        pub const IOCM_DTR = 0x2;
        pub const IOCM_LE = 0x1;
        pub const IOCM_RI = 0x80;
        pub const IOCM_RNG = 0x80;
        pub const IOCM_RTS = 0x4;
        pub const IOCM_SR = 0x10;
        pub const IOCM_ST = 0x8;
        pub const IOCNOTTY = 0x20007471;
        pub const IOCNXCL = 0x2000740e;
        pub const IOCOUTQ = 0x40047473;
        pub const IOCPKT = 0x80047470;
        pub const IOCPKT_DATA = 0x0;
        pub const IOCPKT_DOSTOP = 0x20;
        pub const IOCPKT_FLUSHREAD = 0x1;
        pub const IOCPKT_FLUSHWRITE = 0x2;
        pub const IOCPKT_IOCTL = 0x40;
        pub const IOCPKT_NOSTOP = 0x10;
        pub const IOCPKT_START = 0x8;
        pub const IOCPKT_STOP = 0x4;
        pub const IOCPTMGET = 0x40287446;
        pub const IOCPTSNAME = 0x40287448;
        pub const IOCRCVFRAME = 0x80087445;
        pub const IOCREMOTE = 0x80047469;
        pub const IOCSBRK = 0x2000747b;
        pub const IOCSCTTY = 0x20007461;
        pub const IOCSDTR = 0x20007479;
        pub const IOCSETA = 0x802c7414;
        pub const IOCSETAF = 0x802c7416;
        pub const IOCSETAW = 0x802c7415;
        pub const IOCSETD = 0x8004741b;
        pub const IOCSFLAGS = 0x8004745c;
        pub const IOCSIG = 0x2000745f;
        pub const IOCSLINED = 0x80207443;
        pub const IOCSPGRP = 0x80047476;
        pub const IOCSQSIZE = 0x80047480;
        pub const IOCSSIZE = 0x80087467;
        pub const IOCSTART = 0x2000746e;
        pub const IOCSTAT = 0x80047465;
        pub const IOCSTI = 0x80017472;
        pub const IOCSTOP = 0x2000746f;
        pub const IOCSWINSZ = 0x80087467;
        pub const IOCUCNTL = 0x80047466;
        pub const IOCXMTFRAME = 0x80087444;
    },
    .haiku => struct {
        pub const CGETA = 0x8000;
        pub const CSETA = 0x8001;
        pub const CSETAF = 0x8002;
        pub const CSETAW = 0x8003;
        pub const CWAITEVENT = 0x8004;
        pub const CSBRK = 0x8005;
        pub const CFLSH = 0x8006;
        pub const CXONC = 0x8007;
        pub const CQUERYCONNECTED = 0x8008;
        pub const CGETBITS = 0x8009;
        pub const CSETDTR = 0x8010;
        pub const CSETRTS = 0x8011;
        pub const IOCGWINSZ = 0x8012;
        pub const IOCSWINSZ = 0x8013;
        pub const CVTIME = 0x8014;
        pub const IOCGPGRP = 0x8015;
        pub const IOCSPGRP = 0x8016;
        pub const IOCSCTTY = 0x8017;
        pub const IOCMGET = 0x8018;
        pub const IOCMSET = 0x8019;
        pub const IOCSBRK = 0x8020;
        pub const IOCCBRK = 0x8021;
        pub const IOCMBIS = 0x8022;
        pub const IOCMBIC = 0x8023;
        pub const IOCGSID = 0x8024;

        pub const FIONREAD = 0xbe000001;
        pub const FIONBIO = 0xbe000000;
    },
    .openbsd => struct {
        pub const IOCCBRK = 0x2000747a;
        pub const IOCCDTR = 0x20007478;
        pub const IOCCONS = 0x80047462;
        pub const IOCDCDTIMESTAMP = 0x40107458;
        pub const IOCDRAIN = 0x2000745e;
        pub const IOCEXCL = 0x2000740d;
        pub const IOCEXT = 0x80047460;
        pub const IOCFLAG_CDTRCTS = 0x10;
        pub const IOCFLAG_CLOCAL = 0x2;
        pub const IOCFLAG_CRTSCTS = 0x4;
        pub const IOCFLAG_MDMBUF = 0x8;
        pub const IOCFLAG_SOFTCAR = 0x1;
        pub const IOCFLUSH = 0x80047410;
        pub const IOCGETA = 0x402c7413;
        pub const IOCGETD = 0x4004741a;
        pub const IOCGFLAGS = 0x4004745d;
        pub const IOCGLINED = 0x40207442;
        pub const IOCGPGRP = 0x40047477;
        pub const IOCGQSIZE = 0x40047481;
        pub const IOCGRANTPT = 0x20007447;
        pub const IOCGSID = 0x40047463;
        pub const IOCGSIZE = 0x40087468;
        pub const IOCGWINSZ = 0x40087468;
        pub const IOCMBIC = 0x8004746b;
        pub const IOCMBIS = 0x8004746c;
        pub const IOCMGET = 0x4004746a;
        pub const IOCMSET = 0x8004746d;
        pub const IOCM_CAR = 0x40;
        pub const IOCM_CD = 0x40;
        pub const IOCM_CTS = 0x20;
        pub const IOCM_DSR = 0x100;
        pub const IOCM_DTR = 0x2;
        pub const IOCM_LE = 0x1;
        pub const IOCM_RI = 0x80;
        pub const IOCM_RNG = 0x80;
        pub const IOCM_RTS = 0x4;
        pub const IOCM_SR = 0x10;
        pub const IOCM_ST = 0x8;
        pub const IOCNOTTY = 0x20007471;
        pub const IOCNXCL = 0x2000740e;
        pub const IOCOUTQ = 0x40047473;
        pub const IOCPKT = 0x80047470;
        pub const IOCPKT_DATA = 0x0;
        pub const IOCPKT_DOSTOP = 0x20;
        pub const IOCPKT_FLUSHREAD = 0x1;
        pub const IOCPKT_FLUSHWRITE = 0x2;
        pub const IOCPKT_IOCTL = 0x40;
        pub const IOCPKT_NOSTOP = 0x10;
        pub const IOCPKT_START = 0x8;
        pub const IOCPKT_STOP = 0x4;
        pub const IOCPTMGET = 0x40287446;
        pub const IOCPTSNAME = 0x40287448;
        pub const IOCRCVFRAME = 0x80087445;
        pub const IOCREMOTE = 0x80047469;
        pub const IOCSBRK = 0x2000747b;
        pub const IOCSCTTY = 0x20007461;
        pub const IOCSDTR = 0x20007479;
        pub const IOCSETA = 0x802c7414;
        pub const IOCSETAF = 0x802c7416;
        pub const IOCSETAW = 0x802c7415;
        pub const IOCSETD = 0x8004741b;
        pub const IOCSFLAGS = 0x8004745c;
        pub const IOCSIG = 0x2000745f;
        pub const IOCSLINED = 0x80207443;
        pub const IOCSPGRP = 0x80047476;
        pub const IOCSQSIZE = 0x80047480;
        pub const IOCSSIZE = 0x80087467;
        pub const IOCSTART = 0x2000746e;
        pub const IOCSTAT = 0x80047465;
        pub const IOCSTI = 0x80017472;
        pub const IOCSTOP = 0x2000746f;
        pub const IOCSWINSZ = 0x80087467;
        pub const IOCUCNTL = 0x80047466;
        pub const IOCXMTFRAME = 0x80087444;
    },
    .dragonfly => struct {
        pub const IOCMODG = 0x40047403;
        pub const IOCMODS = 0x80047404;
        pub const IOCM_LE = 0x00000001;
        pub const IOCM_DTR = 0x00000002;
        pub const IOCM_RTS = 0x00000004;
        pub const IOCM_ST = 0x00000008;
        pub const IOCM_SR = 0x00000010;
        pub const IOCM_CTS = 0x00000020;
        pub const IOCM_CAR = 0x00000040;
        pub const IOCM_CD = 0x00000040;
        pub const IOCM_RNG = 0x00000080;
        pub const IOCM_RI = 0x00000080;
        pub const IOCM_DSR = 0x00000100;
        pub const IOCEXCL = 0x2000740d;
        pub const IOCNXCL = 0x2000740e;
        pub const IOCFLUSH = 0x80047410;
        pub const IOCGETA = 0x402c7413;
        pub const IOCSETA = 0x802c7414;
        pub const IOCSETAW = 0x802c7415;
        pub const IOCSETAF = 0x802c7416;
        pub const IOCGETD = 0x4004741a;
        pub const IOCSETD = 0x8004741b;
        pub const IOCSBRK = 0x2000747b;
        pub const IOCCBRK = 0x2000747a;
        pub const IOCSDTR = 0x20007479;
        pub const IOCCDTR = 0x20007478;
        pub const IOCGPGRP = 0x40047477;
        pub const IOCSPGRP = 0x80047476;
        pub const IOCOUTQ = 0x40047473;
        pub const IOCSTI = 0x80017472;
        pub const IOCNOTTY = 0x20007471;
        pub const IOCPKT = 0x80047470;
        pub const IOCPKT_DATA = 0x00000000;
        pub const IOCPKT_FLUSHREAD = 0x00000001;
        pub const IOCPKT_FLUSHWRITE = 0x00000002;
        pub const IOCPKT_STOP = 0x00000004;
        pub const IOCPKT_START = 0x00000008;
        pub const IOCPKT_NOSTOP = 0x00000010;
        pub const IOCPKT_DOSTOP = 0x00000020;
        pub const IOCPKT_IOCTL = 0x00000040;
        pub const IOCSTOP = 0x2000746f;
        pub const IOCSTART = 0x2000746e;
        pub const IOCMSET = 0x8004746d;
        pub const IOCMBIS = 0x8004746c;
        pub const IOCMBIC = 0x8004746b;
        pub const IOCMGET = 0x4004746a;
        pub const IOCREMOTE = 0x80047469;
        pub const IOCGWINSZ = 0x40087468;
        pub const IOCSWINSZ = 0x80087467;
        pub const IOCUCNTL = 0x80047466;
        pub const IOCSTAT = 0x20007465;
        pub const IOCGSID = 0x40047463;
        pub const IOCCONS = 0x80047462;
        pub const IOCSCTTY = 0x20007461;
        pub const IOCEXT = 0x80047460;
        pub const IOCSIG = 0x2000745f;
        pub const IOCDRAIN = 0x2000745e;
        pub const IOCMSDTRWAIT = 0x8004745b;
        pub const IOCMGDTRWAIT = 0x4004745a;
        pub const IOCTIMESTAMP = 0x40107459;
        pub const IOCDCDTIMESTAMP = 0x40107458;
        pub const IOCSDRAINWAIT = 0x80047457;
        pub const IOCGDRAINWAIT = 0x40047456;
        pub const IOCISPTMASTER = 0x20007455;
    },
    else => void,
};
pub const IOCPARM_MASK = switch (native_os) {
    .windows => ws2_32.IOCPARM_MASK,
    .macos, .ios, .tvos, .watchos, .visionos => 0x1fff,
    else => void,
};
pub const TCSA = std.posix.TCSA;
pub const TFD = switch (native_os) {
    .linux => linux.TFD,
    else => void,
};
pub const VDSO = switch (native_os) {
    .linux => linux.VDSO,
    else => void,
};
pub const W = switch (native_os) {
    .linux => linux.W,
    .emscripten => emscripten.W,
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        /// [XSI] no hang in wait/no child to reap
        pub const NOHANG = 0x00000001;
        /// [XSI] notify on stop, untraced child
        pub const UNTRACED = 0x00000002;

        pub fn EXITSTATUS(x: u32) u8 {
            return @as(u8, @intCast(x >> 8));
        }
        pub fn TERMSIG(x: u32) u32 {
            return status(x);
        }
        pub fn STOPSIG(x: u32) u32 {
            return x >> 8;
        }
        pub fn IFEXITED(x: u32) bool {
            return status(x) == 0;
        }
        pub fn IFSTOPPED(x: u32) bool {
            return status(x) == stopped and STOPSIG(x) != 0x13;
        }
        pub fn IFSIGNALED(x: u32) bool {
            return status(x) != stopped and status(x) != 0;
        }

        fn status(x: u32) u32 {
            return x & 0o177;
        }
        const stopped = 0o177;
    },
    .freebsd => struct {
        pub const NOHANG = 1;
        pub const UNTRACED = 2;
        pub const STOPPED = UNTRACED;
        pub const CONTINUED = 4;
        pub const NOWAIT = 8;
        pub const EXITED = 16;
        pub const TRAPPED = 32;

        pub fn EXITSTATUS(s: u32) u8 {
            return @as(u8, @intCast((s & 0xff00) >> 8));
        }
        pub fn TERMSIG(s: u32) u32 {
            return s & 0x7f;
        }
        pub fn STOPSIG(s: u32) u32 {
            return EXITSTATUS(s);
        }
        pub fn IFEXITED(s: u32) bool {
            return TERMSIG(s) == 0;
        }
        pub fn IFSTOPPED(s: u32) bool {
            return @as(u16, @truncate((((s & 0xffff) *% 0x10001) >> 8))) > 0x7f00;
        }
        pub fn IFSIGNALED(s: u32) bool {
            return (s & 0xffff) -% 1 < 0xff;
        }
    },
    .solaris, .illumos => struct {
        pub const EXITED = 0o001;
        pub const TRAPPED = 0o002;
        pub const UNTRACED = 0o004;
        pub const STOPPED = UNTRACED;
        pub const CONTINUED = 0o010;
        pub const NOHANG = 0o100;
        pub const NOWAIT = 0o200;

        pub fn EXITSTATUS(s: u32) u8 {
            return @as(u8, @intCast((s >> 8) & 0xff));
        }
        pub fn TERMSIG(s: u32) u32 {
            return s & 0x7f;
        }
        pub fn STOPSIG(s: u32) u32 {
            return EXITSTATUS(s);
        }
        pub fn IFEXITED(s: u32) bool {
            return TERMSIG(s) == 0;
        }

        pub fn IFCONTINUED(s: u32) bool {
            return ((s & 0o177777) == 0o177777);
        }

        pub fn IFSTOPPED(s: u32) bool {
            return (s & 0x00ff != 0o177) and !(s & 0xff00 != 0);
        }

        pub fn IFSIGNALED(s: u32) bool {
            return s & 0x00ff > 0 and s & 0xff00 == 0;
        }
    },
    .netbsd => struct {
        pub const NOHANG = 0x00000001;
        pub const UNTRACED = 0x00000002;
        pub const STOPPED = UNTRACED;
        pub const CONTINUED = 0x00000010;
        pub const NOWAIT = 0x00010000;
        pub const EXITED = 0x00000020;
        pub const TRAPPED = 0x00000040;

        pub fn EXITSTATUS(s: u32) u8 {
            return @as(u8, @intCast((s >> 8) & 0xff));
        }
        pub fn TERMSIG(s: u32) u32 {
            return s & 0x7f;
        }
        pub fn STOPSIG(s: u32) u32 {
            return EXITSTATUS(s);
        }
        pub fn IFEXITED(s: u32) bool {
            return TERMSIG(s) == 0;
        }

        pub fn IFCONTINUED(s: u32) bool {
            return ((s & 0x7f) == 0xffff);
        }

        pub fn IFSTOPPED(s: u32) bool {
            return ((s & 0x7f != 0x7f) and !IFCONTINUED(s));
        }

        pub fn IFSIGNALED(s: u32) bool {
            return !IFSTOPPED(s) and !IFCONTINUED(s) and !IFEXITED(s);
        }
    },
    .dragonfly => struct {
        pub const NOHANG = 0x0001;
        pub const UNTRACED = 0x0002;
        pub const CONTINUED = 0x0004;
        pub const STOPPED = UNTRACED;
        pub const NOWAIT = 0x0008;
        pub const EXITED = 0x0010;
        pub const TRAPPED = 0x0020;

        pub fn EXITSTATUS(s: u32) u8 {
            return @as(u8, @intCast((s & 0xff00) >> 8));
        }
        pub fn TERMSIG(s: u32) u32 {
            return s & 0x7f;
        }
        pub fn STOPSIG(s: u32) u32 {
            return EXITSTATUS(s);
        }
        pub fn IFEXITED(s: u32) bool {
            return TERMSIG(s) == 0;
        }
        pub fn IFSTOPPED(s: u32) bool {
            return @as(u16, @truncate((((s & 0xffff) *% 0x10001) >> 8))) > 0x7f00;
        }
        pub fn IFSIGNALED(s: u32) bool {
            return (s & 0xffff) -% 1 < 0xff;
        }
    },
    .haiku => struct {
        pub const NOHANG = 0x1;
        pub const UNTRACED = 0x2;
        pub const CONTINUED = 0x4;
        pub const EXITED = 0x08;
        pub const STOPPED = 0x10;
        pub const NOWAIT = 0x20;

        pub fn EXITSTATUS(s: u32) u8 {
            return @as(u8, @intCast(s & 0xff));
        }

        pub fn TERMSIG(s: u32) u32 {
            return (s >> 8) & 0xff;
        }

        pub fn STOPSIG(s: u32) u32 {
            return (s >> 16) & 0xff;
        }

        pub fn IFEXITED(s: u32) bool {
            return (s & ~@as(u32, 0xff)) == 0;
        }

        pub fn IFSTOPPED(s: u32) bool {
            return ((s >> 16) & 0xff) != 0;
        }

        pub fn IFSIGNALED(s: u32) bool {
            return ((s >> 8) & 0xff) != 0;
        }
    },
    .openbsd => struct {
        pub const NOHANG = 1;
        pub const UNTRACED = 2;
        pub const CONTINUED = 8;

        pub fn EXITSTATUS(s: u32) u8 {
            return @as(u8, @intCast((s >> 8) & 0xff));
        }
        pub fn TERMSIG(s: u32) u32 {
            return (s & 0x7f);
        }
        pub fn STOPSIG(s: u32) u32 {
            return EXITSTATUS(s);
        }
        pub fn IFEXITED(s: u32) bool {
            return TERMSIG(s) == 0;
        }

        pub fn IFCONTINUED(s: u32) bool {
            return ((s & 0o177777) == 0o177777);
        }

        pub fn IFSTOPPED(s: u32) bool {
            return (s & 0xff == 0o177);
        }

        pub fn IFSIGNALED(s: u32) bool {
            return (((s) & 0o177) != 0o177) and (((s) & 0o177) != 0);
        }
    },
    else => void,
};
pub const clock_t = switch (native_os) {
    .linux => linux.clock_t,
    .emscripten => emscripten.clock_t,
    .macos, .ios, .tvos, .watchos, .visionos => c_ulong,
    .freebsd => isize,
    .openbsd, .solaris, .illumos => i64,
    .netbsd => u32,
    .haiku => i32,
    else => void,
};
pub const cpu_set_t = switch (native_os) {
    .linux => linux.cpu_set_t,
    .emscripten => emscripten.cpu_set_t,
    else => void,
};
pub const dl_phdr_info = switch (native_os) {
    .linux => linux.dl_phdr_info,
    .emscripten => emscripten.dl_phdr_info,
    .freebsd => extern struct {
        /// Module relocation base.
        addr: if (builtin.target.ptrBitWidth() == 32) std.elf.Elf32_Addr else std.elf.Elf64_Addr,
        /// Module name.
        name: ?[*:0]const u8,
        /// Pointer to module's phdr.
        phdr: [*]std.elf.Phdr,
        /// Number of entries in phdr.
        phnum: u16,
        /// Total number of loads.
        adds: u64,
        /// Total number of unloads.
        subs: u64,
        tls_modid: usize,
        tls_data: ?*anyopaque,
    },
    .solaris, .illumos => extern struct {
        addr: std.elf.Addr,
        name: ?[*:0]const u8,
        phdr: [*]std.elf.Phdr,
        phnum: std.elf.Half,
        /// Incremented when a new object is mapped into the process.
        adds: u64,
        /// Incremented when an object is unmapped from the process.
        subs: u64,
    },
    .openbsd, .haiku, .dragonfly, .netbsd => extern struct {
        addr: usize,
        name: ?[*:0]const u8,
        phdr: [*]std.elf.Phdr,
        phnum: u16,
    },
    else => void,
};
pub const epoll_event = switch (native_os) {
    .linux => linux.epoll_event,
    else => void,
};
pub const ifreq = switch (native_os) {
    .linux => linux.ifreq,
    .emscripten => emscripten.ifreq,
    .solaris, .illumos => lifreq,
    else => void,
};
pub const itimerspec = switch (native_os) {
    .linux => linux.itimerspec,
    .haiku => extern struct {
        interval: timespec,
        value: timespec,
    },
    else => void,
};
pub const msghdr = switch (native_os) {
    .linux => linux.msghdr,
    .openbsd, .emscripten, .dragonfly, .freebsd, .netbsd, .haiku, .solaris, .illumos => extern struct {
        /// optional address
        name: ?*sockaddr,
        /// size of address
        namelen: socklen_t,
        /// scatter/gather array
        iov: [*]iovec,
        /// # elements in iov
        iovlen: i32,
        /// ancillary data
        control: ?*anyopaque,
        /// ancillary data buffer len
        controllen: socklen_t,
        /// flags on received message
        flags: i32,
    },
    else => void,
};
pub const msghdr_const = switch (native_os) {
    .linux => linux.msghdr_const,
    .openbsd, .emscripten, .dragonfly, .freebsd, .netbsd, .haiku, .solaris, .illumos => extern struct {
        /// optional address
        name: ?*const sockaddr,
        /// size of address
        namelen: socklen_t,
        /// scatter/gather array
        iov: [*]const iovec_const,
        /// # elements in iov
        iovlen: i32,
        /// ancillary data
        control: ?*const anyopaque,
        /// ancillary data buffer len
        controllen: socklen_t,
        /// flags on received message
        flags: i32,
    },
    else => void,
};
pub const nfds_t = switch (native_os) {
    .linux => linux.nfds_t,
    .emscripten => emscripten.nfds_t,
    .haiku, .solaris, .illumos, .wasi => usize,
    .windows => c_ulong,
    .openbsd, .dragonfly, .netbsd, .freebsd, .macos, .ios, .tvos, .watchos, .visionos => u32,
    else => void,
};
pub const perf_event_attr = switch (native_os) {
    .linux => linux.perf_event_attr,
    else => void,
};
pub const pid_t = switch (native_os) {
    .linux => linux.pid_t,
    .emscripten => emscripten.pid_t,
    .windows => windows.HANDLE,
    else => i32,
};
pub const pollfd = switch (native_os) {
    .linux => linux.pollfd,
    .emscripten => emscripten.pollfd,
    .windows => ws2_32.pollfd,
    else => extern struct {
        fd: fd_t,
        events: i16,
        revents: i16,
    },
};
pub const rlim_t = switch (native_os) {
    .linux => linux.rlim_t,
    .emscripten => emscripten.rlim_t,
    .openbsd, .netbsd, .solaris, .illumos, .macos, .ios, .tvos, .watchos, .visionos => u64,
    .haiku, .dragonfly, .freebsd => i64,
    else => void,
};
pub const rlimit = switch (native_os) {
    .linux, .emscripten => linux.rlimit,
    .windows => void,
    else => extern struct {
        /// Soft limit
        cur: rlim_t,
        /// Hard limit
        max: rlim_t,
    },
};
pub const rlimit_resource = switch (native_os) {
    .linux => linux.rlimit_resource,
    .emscripten => emscripten.rlimit_resource,
    .openbsd, .macos, .ios, .tvos, .watchos, .visionos => enum(c_int) {
        CPU = 0,
        FSIZE = 1,
        DATA = 2,
        STACK = 3,
        CORE = 4,
        RSS = 5,
        MEMLOCK = 6,
        NPROC = 7,
        NOFILE = 8,
        _,

        pub const AS: rlimit_resource = .RSS;
    },
    .freebsd => enum(c_int) {
        CPU = 0,
        FSIZE = 1,
        DATA = 2,
        STACK = 3,
        CORE = 4,
        RSS = 5,
        MEMLOCK = 6,
        NPROC = 7,
        NOFILE = 8,
        SBSIZE = 9,
        VMEM = 10,
        NPTS = 11,
        SWAP = 12,
        KQUEUES = 13,
        UMTXP = 14,
        _,

        pub const AS: rlimit_resource = .VMEM;
    },
    .solaris, .illumos => enum(c_int) {
        CPU = 0,
        FSIZE = 1,
        DATA = 2,
        STACK = 3,
        CORE = 4,
        NOFILE = 5,
        VMEM = 6,
        _,

        pub const AS: rlimit_resource = .VMEM;
    },
    .netbsd => enum(c_int) {
        CPU = 0,
        FSIZE = 1,
        DATA = 2,
        STACK = 3,
        CORE = 4,
        RSS = 5,
        MEMLOCK = 6,
        NPROC = 7,
        NOFILE = 8,
        SBSIZE = 9,
        VMEM = 10,
        NTHR = 11,
        _,

        pub const AS: rlimit_resource = .VMEM;
    },
    .dragonfly => enum(c_int) {
        CPU = 0,
        FSIZE = 1,
        DATA = 2,
        STACK = 3,
        CORE = 4,
        RSS = 5,
        MEMLOCK = 6,
        NPROC = 7,
        NOFILE = 8,
        SBSIZE = 9,
        VMEM = 10,
        POSIXLOCKS = 11,
        _,

        pub const AS: rlimit_resource = .VMEM;
    },
    .haiku => enum(i32) {
        CORE = 0,
        CPU = 1,
        DATA = 2,
        FSIZE = 3,
        NOFILE = 4,
        STACK = 5,
        AS = 6,
        NOVMON = 7,
        _,
    },
    else => void,
};
pub const rusage = switch (native_os) {
    .linux => linux.rusage,
    .emscripten => emscripten.rusage,
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        utime: timeval,
        stime: timeval,
        maxrss: isize,
        ixrss: isize,
        idrss: isize,
        isrss: isize,
        minflt: isize,
        majflt: isize,
        nswap: isize,
        inblock: isize,
        oublock: isize,
        msgsnd: isize,
        msgrcv: isize,
        nsignals: isize,
        nvcsw: isize,
        nivcsw: isize,

        pub const SELF = 0;
        pub const CHILDREN = -1;
    },
    .solaris, .illumos => extern struct {
        utime: timeval,
        stime: timeval,
        maxrss: isize,
        ixrss: isize,
        idrss: isize,
        isrss: isize,
        minflt: isize,
        majflt: isize,
        nswap: isize,
        inblock: isize,
        oublock: isize,
        msgsnd: isize,
        msgrcv: isize,
        nsignals: isize,
        nvcsw: isize,
        nivcsw: isize,

        pub const SELF = 0;
        pub const CHILDREN = -1;
        pub const THREAD = 1;
    },
    else => void,
};

pub const siginfo_t = switch (native_os) {
    .linux => linux.siginfo_t,
    .emscripten => emscripten.siginfo_t,
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        signo: c_int,
        errno: c_int,
        code: c_int,
        pid: pid_t,
        uid: uid_t,
        status: c_int,
        addr: *allowzero anyopaque,
        value: extern union {
            int: c_int,
            ptr: *anyopaque,
        },
        si_band: c_long,
        _pad: [7]c_ulong,
    },
    .freebsd => extern struct {
        // Signal number.
        signo: c_int,
        // Errno association.
        errno: c_int,
        /// Signal code.
        ///
        /// Cause of signal, one of the SI_ macros or signal-specific values, i.e.
        /// one of the FPE_... values for SIGFPE.
        /// This value is equivalent to the second argument to an old-style FreeBSD
        /// signal handler.
        code: c_int,
        /// Sending process.
        pid: pid_t,
        /// Sender's ruid.
        uid: uid_t,
        /// Exit value.
        status: c_int,
        /// Faulting instruction.
        addr: *allowzero anyopaque,
        /// Signal value.
        value: sigval,
        reason: extern union {
            fault: extern struct {
                /// Machine specific trap code.
                trapno: c_int,
            },
            timer: extern struct {
                timerid: c_int,
                overrun: c_int,
            },
            mesgq: extern struct {
                mqd: c_int,
            },
            poll: extern struct {
                /// Band event for SIGPOLL. UNUSED.
                band: c_long,
            },
            spare: extern struct {
                spare1: c_long,
                spare2: [7]c_int,
            },
        },
    },
    .solaris, .illumos => extern struct {
        signo: c_int,
        code: c_int,
        errno: c_int,
        // 64bit architectures insert 4bytes of padding here, this is done by
        // correctly aligning the reason field
        reason: extern union {
            proc: extern struct {
                pid: pid_t,
                pdata: extern union {
                    kill: extern struct {
                        uid: uid_t,
                        value: sigval_t,
                    },
                    cld: extern struct {
                        utime: clock_t,
                        status: c_int,
                        stime: clock_t,
                    },
                },
                contract: solaris.ctid_t,
                zone: solaris.zoneid_t,
            },
            fault: extern struct {
                addr: *allowzero anyopaque,
                trapno: c_int,
                pc: ?*anyopaque,
            },
            file: extern struct {
                // fd not currently available for SIGPOLL.
                fd: c_int,
                band: c_long,
            },
            prof: extern struct {
                addr: ?*anyopaque,
                timestamp: timespec,
                syscall: c_short,
                sysarg: u8,
                fault: u8,
                args: [8]c_long,
                state: [10]c_int,
            },
            rctl: extern struct {
                entity: i32,
            },
            __pad: [256 - 4 * @sizeOf(c_int)]u8,
        } align(@sizeOf(usize)),

        comptime {
            assert(@sizeOf(@This()) == 256);
            assert(@alignOf(@This()) == @sizeOf(usize));
        }
    },
    .netbsd => extern union {
        pad: [128]u8,
        info: netbsd._ksiginfo,
    },
    .dragonfly => extern struct {
        signo: c_int,
        errno: c_int,
        code: c_int,
        pid: c_int,
        uid: uid_t,
        status: c_int,
        addr: *allowzero anyopaque,
        value: sigval,
        band: c_long,
        __spare__: [7]c_int,
    },
    .haiku => extern struct {
        signo: i32,
        code: i32,
        errno: i32,

        pid: pid_t,
        uid: uid_t,
        addr: *allowzero anyopaque,
    },
    .openbsd => extern struct {
        signo: c_int,
        code: c_int,
        errno: c_int,
        data: extern union {
            proc: extern struct {
                pid: pid_t,
                pdata: extern union {
                    kill: extern struct {
                        uid: uid_t,
                        value: sigval,
                    },
                    cld: extern struct {
                        utime: clock_t,
                        stime: clock_t,
                        status: c_int,
                    },
                },
            },
            fault: extern struct {
                addr: *allowzero anyopaque,
                trapno: c_int,
            },
            __pad: [128 - 3 * @sizeOf(c_int)]u8,
        },

        comptime {
            if (@sizeOf(usize) == 4)
                assert(@sizeOf(@This()) == 128)
            else
                // Take into account the padding between errno and data fields.
                assert(@sizeOf(@This()) == 136);
        }
    },
    else => void,
};
pub const sigset_t = switch (native_os) {
    .linux => linux.sigset_t,
    .emscripten => emscripten.sigset_t,
    .openbsd, .macos, .ios, .tvos, .watchos, .visionos => u32,
    .dragonfly, .netbsd, .solaris, .illumos, .freebsd => extern struct {
        __bits: [SIG.WORDS]u32,
    },
    .haiku => u64,
    else => u0,
};
pub const empty_sigset: sigset_t = switch (native_os) {
    .linux => linux.empty_sigset,
    .emscripten => emscripten.empty_sigset,
    .dragonfly, .netbsd, .solaris, .illumos, .freebsd => .{ .__bits = [_]u32{0} ** SIG.WORDS },
    else => 0,
};
pub const filled_sigset = switch (native_os) {
    .linux => linux.filled_sigset,
    .haiku => ~@as(sigset_t, 0),
    else => 0,
};
pub const sigval = switch (native_os) {
    .linux => linux.sigval,
    .openbsd, .dragonfly, .freebsd => extern union {
        int: c_int,
        ptr: ?*anyopaque,
    },
    else => void,
};

pub const addrinfo = switch (native_os) {
    .linux, .emscripten => linux.addrinfo,
    .windows => ws2_32.addrinfo,
    .freebsd, .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        flags: AI,
        family: i32,
        socktype: i32,
        protocol: i32,
        addrlen: socklen_t,
        canonname: ?[*:0]u8,
        addr: ?*sockaddr,
        next: ?*addrinfo,
    },
    .solaris, .illumos => extern struct {
        flags: AI,
        family: i32,
        socktype: i32,
        protocol: i32,
        addrlen: socklen_t,
        canonname: ?[*:0]u8,
        addr: ?*sockaddr,
        next: ?*addrinfo,
    },
    .netbsd => extern struct {
        flags: AI,
        family: i32,
        socktype: i32,
        protocol: i32,
        addrlen: socklen_t,
        canonname: ?[*:0]u8,
        addr: ?*sockaddr,
        next: ?*addrinfo,
    },
    .dragonfly => extern struct {
        flags: AI,
        family: i32,
        socktype: i32,
        protocol: i32,
        addrlen: socklen_t,
        canonname: ?[*:0]u8,
        addr: ?*sockaddr,
        next: ?*addrinfo,
    },
    .haiku => extern struct {
        flags: AI,
        family: i32,
        socktype: i32,
        protocol: i32,
        addrlen: socklen_t,
        canonname: ?[*:0]u8,
        addr: ?*sockaddr,
        next: ?*addrinfo,
    },
    .openbsd => extern struct {
        flags: AI,
        family: c_int,
        socktype: c_int,
        protocol: c_int,
        addrlen: socklen_t,
        addr: ?*sockaddr,
        canonname: ?[*:0]u8,
        next: ?*addrinfo,
    },
    else => void,
};
pub const sockaddr = switch (native_os) {
    .linux, .emscripten => linux.sockaddr,
    .windows => ws2_32.sockaddr,
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        len: u8,
        family: sa_family_t,
        data: [14]u8,

        pub const SS_MAXSIZE = 128;
        pub const storage = extern struct {
            len: u8 align(8),
            family: sa_family_t,
            padding: [126]u8 = undefined,

            comptime {
                assert(@sizeOf(storage) == SS_MAXSIZE);
                assert(@alignOf(storage) == 8);
            }
        };
        pub const in = extern struct {
            len: u8 = @sizeOf(in),
            family: sa_family_t = AF.INET,
            port: in_port_t,
            addr: u32,
            zero: [8]u8 = [8]u8{ 0, 0, 0, 0, 0, 0, 0, 0 },
        };
        pub const in6 = extern struct {
            len: u8 = @sizeOf(in6),
            family: sa_family_t = AF.INET6,
            port: in_port_t,
            flowinfo: u32,
            addr: [16]u8,
            scope_id: u32,
        };

        /// UNIX domain socket
        pub const un = extern struct {
            len: u8 = @sizeOf(un),
            family: sa_family_t = AF.UNIX,
            path: [104]u8,
        };
    },
    .freebsd => extern struct {
        /// total length
        len: u8,
        /// address family
        family: sa_family_t,
        /// actually longer; address value
        data: [14]u8,

        pub const SS_MAXSIZE = 128;
        pub const storage = extern struct {
            len: u8 align(8),
            family: sa_family_t,
            padding: [126]u8 = undefined,

            comptime {
                assert(@sizeOf(storage) == SS_MAXSIZE);
                assert(@alignOf(storage) == 8);
            }
        };

        pub const in = extern struct {
            len: u8 = @sizeOf(in),
            family: sa_family_t = AF.INET,
            port: in_port_t,
            addr: u32,
            zero: [8]u8 = [8]u8{ 0, 0, 0, 0, 0, 0, 0, 0 },
        };

        pub const in6 = extern struct {
            len: u8 = @sizeOf(in6),
            family: sa_family_t = AF.INET6,
            port: in_port_t,
            flowinfo: u32,
            addr: [16]u8,
            scope_id: u32,
        };

        pub const un = extern struct {
            len: u8 = @sizeOf(un),
            family: sa_family_t = AF.UNIX,
            path: [104]u8,
        };
    },
    .solaris, .illumos => extern struct {
        /// address family
        family: sa_family_t,

        /// actually longer; address value
        data: [14]u8,

        pub const SS_MAXSIZE = 256;
        pub const storage = extern struct {
            family: sa_family_t align(8),
            padding: [254]u8 = undefined,

            comptime {
                assert(@sizeOf(storage) == SS_MAXSIZE);
                assert(@alignOf(storage) == 8);
            }
        };

        pub const in = extern struct {
            family: sa_family_t = AF.INET,
            port: in_port_t,
            addr: u32,
            zero: [8]u8 = [8]u8{ 0, 0, 0, 0, 0, 0, 0, 0 },
        };

        pub const in6 = extern struct {
            family: sa_family_t = AF.INET6,
            port: in_port_t,
            flowinfo: u32,
            addr: [16]u8,
            scope_id: u32,
            __src_id: u32 = 0,
        };

        /// Definitions for UNIX IPC domain.
        pub const un = extern struct {
            family: sa_family_t = AF.UNIX,
            path: [108]u8,
        };
    },
    .netbsd => extern struct {
        /// total length
        len: u8,
        /// address family
        family: sa_family_t,
        /// actually longer; address value
        data: [14]u8,

        pub const SS_MAXSIZE = 128;
        pub const storage = extern struct {
            len: u8 align(8),
            family: sa_family_t,
            padding: [126]u8 = undefined,

            comptime {
                assert(@sizeOf(storage) == SS_MAXSIZE);
                assert(@alignOf(storage) == 8);
            }
        };

        pub const in = extern struct {
            len: u8 = @sizeOf(in),
            family: sa_family_t = AF.INET,
            port: in_port_t,
            addr: u32,
            zero: [8]u8 = [8]u8{ 0, 0, 0, 0, 0, 0, 0, 0 },
        };

        pub const in6 = extern struct {
            len: u8 = @sizeOf(in6),
            family: sa_family_t = AF.INET6,
            port: in_port_t,
            flowinfo: u32,
            addr: [16]u8,
            scope_id: u32,
        };

        /// Definitions for UNIX IPC domain.
        pub const un = extern struct {
            /// total sockaddr length
            len: u8 = @sizeOf(un),

            family: sa_family_t = AF.LOCAL,

            /// path name
            path: [104]u8,
        };
    },
    .dragonfly => extern struct {
        len: u8,
        family: sa_family_t,
        data: [14]u8,

        pub const SS_MAXSIZE = 128;
        pub const storage = extern struct {
            len: u8 align(8),
            family: sa_family_t,
            padding: [126]u8 = undefined,

            comptime {
                assert(@sizeOf(storage) == SS_MAXSIZE);
                assert(@alignOf(storage) == 8);
            }
        };

        pub const in = extern struct {
            len: u8 = @sizeOf(in),
            family: sa_family_t = AF.INET,
            port: in_port_t,
            addr: u32,
            zero: [8]u8 = [8]u8{ 0, 0, 0, 0, 0, 0, 0, 0 },
        };

        pub const in6 = extern struct {
            len: u8 = @sizeOf(in6),
            family: sa_family_t = AF.INET6,
            port: in_port_t,
            flowinfo: u32,
            addr: [16]u8,
            scope_id: u32,
        };

        pub const un = extern struct {
            len: u8 = @sizeOf(un),
            family: sa_family_t = AF.UNIX,
            path: [104]u8,
        };
    },
    .haiku => extern struct {
        /// total length
        len: u8,
        /// address family
        family: sa_family_t,
        /// actually longer; address value
        data: [14]u8,

        pub const SS_MAXSIZE = 128;
        pub const storage = extern struct {
            len: u8 align(8),
            family: sa_family_t,
            padding: [126]u8 = undefined,

            comptime {
                assert(@sizeOf(storage) == SS_MAXSIZE);
                assert(@alignOf(storage) == 8);
            }
        };

        pub const in = extern struct {
            len: u8 = @sizeOf(in),
            family: sa_family_t = AF.INET,
            port: in_port_t,
            addr: u32,
            zero: [8]u8 = [8]u8{ 0, 0, 0, 0, 0, 0, 0, 0 },
        };

        pub const in6 = extern struct {
            len: u8 = @sizeOf(in6),
            family: sa_family_t = AF.INET6,
            port: in_port_t,
            flowinfo: u32,
            addr: [16]u8,
            scope_id: u32,
        };

        pub const un = extern struct {
            len: u8 = @sizeOf(un),
            family: sa_family_t = AF.UNIX,
            path: [104]u8,
        };
    },
    .openbsd => extern struct {
        /// total length
        len: u8,
        /// address family
        family: sa_family_t,
        /// actually longer; address value
        data: [14]u8,

        pub const SS_MAXSIZE = 256;
        pub const storage = extern struct {
            len: u8 align(8),
            family: sa_family_t,
            padding: [254]u8 = undefined,

            comptime {
                assert(@sizeOf(storage) == SS_MAXSIZE);
                assert(@alignOf(storage) == 8);
            }
        };

        pub const in = extern struct {
            len: u8 = @sizeOf(in),
            family: sa_family_t = AF.INET,
            port: in_port_t,
            addr: u32,
            zero: [8]u8 = [8]u8{ 0, 0, 0, 0, 0, 0, 0, 0 },
        };

        pub const in6 = extern struct {
            len: u8 = @sizeOf(in6),
            family: sa_family_t = AF.INET6,
            port: in_port_t,
            flowinfo: u32,
            addr: [16]u8,
            scope_id: u32,
        };

        /// Definitions for UNIX IPC domain.
        pub const un = extern struct {
            /// total sockaddr length
            len: u8 = @sizeOf(un),

            family: sa_family_t = AF.LOCAL,

            /// path name
            path: [104]u8,
        };
    },
    else => void,
};
pub const socklen_t = switch (native_os) {
    .linux, .emscripten => linux.socklen_t,
    .windows => ws2_32.socklen_t,
    else => u32,
};
pub const in_port_t = u16;
pub const sa_family_t = switch (native_os) {
    .linux, .emscripten => linux.sa_family_t,
    .windows => ws2_32.ADDRESS_FAMILY,
    .openbsd, .haiku, .dragonfly, .netbsd, .freebsd, .macos, .ios, .tvos, .watchos, .visionos => u8,
    .solaris, .illumos => u16,
    else => void,
};
pub const AF = switch (native_os) {
    .linux, .emscripten => linux.AF,
    .windows => ws2_32.AF,
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const UNSPEC = 0;
        pub const LOCAL = 1;
        pub const UNIX = LOCAL;
        pub const INET = 2;
        pub const SYS_CONTROL = 2;
        pub const IMPLINK = 3;
        pub const PUP = 4;
        pub const CHAOS = 5;
        pub const NS = 6;
        pub const ISO = 7;
        pub const OSI = ISO;
        pub const ECMA = 8;
        pub const DATAKIT = 9;
        pub const CCITT = 10;
        pub const SNA = 11;
        pub const DECnet = 12;
        pub const DLI = 13;
        pub const LAT = 14;
        pub const HYLINK = 15;
        pub const APPLETALK = 16;
        pub const ROUTE = 17;
        pub const LINK = 18;
        pub const XTP = 19;
        pub const COIP = 20;
        pub const CNT = 21;
        pub const RTIP = 22;
        pub const IPX = 23;
        pub const SIP = 24;
        pub const PIP = 25;
        pub const ISDN = 28;
        pub const E164 = ISDN;
        pub const KEY = 29;
        pub const INET6 = 30;
        pub const NATM = 31;
        pub const SYSTEM = 32;
        pub const NETBIOS = 33;
        pub const PPP = 34;
        pub const MAX = 40;
    },
    .freebsd => struct {
        pub const UNSPEC = 0;
        pub const UNIX = 1;
        pub const LOCAL = UNIX;
        pub const FILE = LOCAL;
        pub const INET = 2;
        pub const IMPLINK = 3;
        pub const PUP = 4;
        pub const CHAOS = 5;
        pub const NETBIOS = 6;
        pub const ISO = 7;
        pub const OSI = ISO;
        pub const ECMA = 8;
        pub const DATAKIT = 9;
        pub const CCITT = 10;
        pub const SNA = 11;
        pub const DECnet = 12;
        pub const DLI = 13;
        pub const LAT = 14;
        pub const HYLINK = 15;
        pub const APPLETALK = 16;
        pub const ROUTE = 17;
        pub const LINK = 18;
        pub const pseudo_XTP = 19;
        pub const COIP = 20;
        pub const CNT = 21;
        pub const pseudo_RTIP = 22;
        pub const IPX = 23;
        pub const SIP = 24;
        pub const pseudo_PIP = 25;
        pub const ISDN = 26;
        pub const E164 = ISDN;
        pub const pseudo_KEY = 27;
        pub const INET6 = 28;
        pub const NATM = 29;
        pub const ATM = 30;
        pub const pseudo_HDRCMPLT = 31;
        pub const NETGRAPH = 32;
        pub const SLOW = 33;
        pub const SCLUSTER = 34;
        pub const ARP = 35;
        pub const BLUETOOTH = 36;
        pub const IEEE80211 = 37;
        pub const INET_SDP = 40;
        pub const INET6_SDP = 42;
        pub const MAX = 42;
    },
    .solaris, .illumos => struct {
        pub const UNSPEC = 0;
        pub const UNIX = 1;
        pub const LOCAL = UNIX;
        pub const FILE = UNIX;
        pub const INET = 2;
        pub const IMPLINK = 3;
        pub const PUP = 4;
        pub const CHAOS = 5;
        pub const NS = 6;
        pub const NBS = 7;
        pub const ECMA = 8;
        pub const DATAKIT = 9;
        pub const CCITT = 10;
        pub const SNA = 11;
        pub const DECnet = 12;
        pub const DLI = 13;
        pub const LAT = 14;
        pub const HYLINK = 15;
        pub const APPLETALK = 16;
        pub const NIT = 17;
        pub const @"802" = 18;
        pub const OSI = 19;
        pub const X25 = 20;
        pub const OSINET = 21;
        pub const GOSIP = 22;
        pub const IPX = 23;
        pub const ROUTE = 24;
        pub const LINK = 25;
        pub const INET6 = 26;
        pub const KEY = 27;
        pub const NCA = 28;
        pub const POLICY = 29;
        pub const INET_OFFLOAD = 30;
        pub const TRILL = 31;
        pub const PACKET = 32;
        pub const LX_NETLINK = 33;
        pub const MAX = 33;
    },
    .netbsd => struct {
        pub const UNSPEC = 0;
        pub const LOCAL = 1;
        pub const UNIX = LOCAL;
        pub const INET = 2;
        pub const IMPLINK = 3;
        pub const PUP = 4;
        pub const CHAOS = 5;
        pub const NS = 6;
        pub const ISO = 7;
        pub const OSI = ISO;
        pub const ECMA = 8;
        pub const DATAKIT = 9;
        pub const CCITT = 10;
        pub const SNA = 11;
        pub const DECnet = 12;
        pub const DLI = 13;
        pub const LAT = 14;
        pub const HYLINK = 15;
        pub const APPLETALK = 16;
        pub const OROUTE = 17;
        pub const LINK = 18;
        pub const COIP = 20;
        pub const CNT = 21;
        pub const IPX = 23;
        pub const INET6 = 24;
        pub const ISDN = 26;
        pub const E164 = ISDN;
        pub const NATM = 27;
        pub const ARP = 28;
        pub const BLUETOOTH = 31;
        pub const IEEE80211 = 32;
        pub const MPLS = 33;
        pub const ROUTE = 34;
        pub const CAN = 35;
        pub const ETHER = 36;
        pub const MAX = 37;
    },
    .dragonfly => struct {
        pub const UNSPEC = 0;
        pub const OSI = ISO;
        pub const UNIX = LOCAL;
        pub const LOCAL = 1;
        pub const INET = 2;
        pub const IMPLINK = 3;
        pub const PUP = 4;
        pub const CHAOS = 5;
        pub const NETBIOS = 6;
        pub const ISO = 7;
        pub const ECMA = 8;
        pub const DATAKIT = 9;
        pub const CCITT = 10;
        pub const SNA = 11;
        pub const DLI = 13;
        pub const LAT = 14;
        pub const HYLINK = 15;
        pub const APPLETALK = 16;
        pub const ROUTE = 17;
        pub const LINK = 18;
        pub const COIP = 20;
        pub const CNT = 21;
        pub const IPX = 23;
        pub const SIP = 24;
        pub const ISDN = 26;
        pub const INET6 = 28;
        pub const NATM = 29;
        pub const ATM = 30;
        pub const NETGRAPH = 32;
        pub const BLUETOOTH = 33;
        pub const MPLS = 34;
        pub const MAX = 36;
    },
    .haiku => struct {
        pub const UNSPEC = 0;
        pub const INET = 1;
        pub const APPLETALK = 2;
        pub const ROUTE = 3;
        pub const LINK = 4;
        pub const INET6 = 5;
        pub const DLI = 6;
        pub const IPX = 7;
        pub const NOTIFY = 8;
        pub const LOCAL = 9;
        pub const UNIX = LOCAL;
        pub const BLUETOOTH = 10;
        pub const MAX = 11;
    },
    .openbsd => struct {
        pub const UNSPEC = 0;
        pub const UNIX = 1;
        pub const LOCAL = UNIX;
        pub const INET = 2;
        pub const APPLETALK = 16;
        pub const INET6 = 24;
        pub const KEY = 30;
        pub const ROUTE = 17;
        pub const SNA = 11;
        pub const MPLS = 33;
        pub const BLUETOOTH = 32;
        pub const ISDN = 26;
        pub const MAX = 36;
    },
    else => void,
};
pub const PF = switch (native_os) {
    .linux, .emscripten => linux.PF,
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const UNSPEC = AF.UNSPEC;
        pub const LOCAL = AF.LOCAL;
        pub const UNIX = PF.LOCAL;
        pub const INET = AF.INET;
        pub const IMPLINK = AF.IMPLINK;
        pub const PUP = AF.PUP;
        pub const CHAOS = AF.CHAOS;
        pub const NS = AF.NS;
        pub const ISO = AF.ISO;
        pub const OSI = AF.ISO;
        pub const ECMA = AF.ECMA;
        pub const DATAKIT = AF.DATAKIT;
        pub const CCITT = AF.CCITT;
        pub const SNA = AF.SNA;
        pub const DECnet = AF.DECnet;
        pub const DLI = AF.DLI;
        pub const LAT = AF.LAT;
        pub const HYLINK = AF.HYLINK;
        pub const APPLETALK = AF.APPLETALK;
        pub const ROUTE = AF.ROUTE;
        pub const LINK = AF.LINK;
        pub const XTP = AF.XTP;
        pub const COIP = AF.COIP;
        pub const CNT = AF.CNT;
        pub const SIP = AF.SIP;
        pub const IPX = AF.IPX;
        pub const RTIP = AF.RTIP;
        pub const PIP = AF.PIP;
        pub const ISDN = AF.ISDN;
        pub const KEY = AF.KEY;
        pub const INET6 = AF.INET6;
        pub const NATM = AF.NATM;
        pub const SYSTEM = AF.SYSTEM;
        pub const NETBIOS = AF.NETBIOS;
        pub const PPP = AF.PPP;
        pub const MAX = AF.MAX;
    },
    .freebsd => struct {
        pub const UNSPEC = AF.UNSPEC;
        pub const LOCAL = AF.LOCAL;
        pub const UNIX = PF.LOCAL;
        pub const INET = AF.INET;
        pub const IMPLINK = AF.IMPLINK;
        pub const PUP = AF.PUP;
        pub const CHAOS = AF.CHAOS;
        pub const NETBIOS = AF.NETBIOS;
        pub const ISO = AF.ISO;
        pub const OSI = AF.ISO;
        pub const ECMA = AF.ECMA;
        pub const DATAKIT = AF.DATAKIT;
        pub const CCITT = AF.CCITT;
        pub const DECnet = AF.DECnet;
        pub const DLI = AF.DLI;
        pub const LAT = AF.LAT;
        pub const HYLINK = AF.HYLINK;
        pub const APPLETALK = AF.APPLETALK;
        pub const ROUTE = AF.ROUTE;
        pub const LINK = AF.LINK;
        pub const XTP = AF.pseudo_XTP;
        pub const COIP = AF.COIP;
        pub const CNT = AF.CNT;
        pub const SIP = AF.SIP;
        pub const IPX = AF.IPX;
        pub const RTIP = AF.pseudo_RTIP;
        pub const PIP = AF.pseudo_PIP;
        pub const ISDN = AF.ISDN;
        pub const KEY = AF.pseudo_KEY;
        pub const INET6 = AF.pseudo_INET6;
        pub const NATM = AF.NATM;
        pub const ATM = AF.ATM;
        pub const NETGRAPH = AF.NETGRAPH;
        pub const SLOW = AF.SLOW;
        pub const SCLUSTER = AF.SCLUSTER;
        pub const ARP = AF.ARP;
        pub const BLUETOOTH = AF.BLUETOOTH;
        pub const IEEE80211 = AF.IEEE80211;
        pub const INET_SDP = AF.INET_SDP;
        pub const INET6_SDP = AF.INET6_SDP;
        pub const MAX = AF.MAX;
    },
    .solaris, .illumos => struct {
        pub const UNSPEC = AF.UNSPEC;
        pub const UNIX = AF.UNIX;
        pub const LOCAL = UNIX;
        pub const FILE = UNIX;
        pub const INET = AF.INET;
        pub const IMPLINK = AF.IMPLINK;
        pub const PUP = AF.PUP;
        pub const CHAOS = AF.CHAOS;
        pub const NS = AF.NS;
        pub const NBS = AF.NBS;
        pub const ECMA = AF.ECMA;
        pub const DATAKIT = AF.DATAKIT;
        pub const CCITT = AF.CCITT;
        pub const SNA = AF.SNA;
        pub const DECnet = AF.DECnet;
        pub const DLI = AF.DLI;
        pub const LAT = AF.LAT;
        pub const HYLINK = AF.HYLINK;
        pub const APPLETALK = AF.APPLETALK;
        pub const NIT = AF.NIT;
        pub const @"802" = AF.@"802";
        pub const OSI = AF.OSI;
        pub const X25 = AF.X25;
        pub const OSINET = AF.OSINET;
        pub const GOSIP = AF.GOSIP;
        pub const IPX = AF.IPX;
        pub const ROUTE = AF.ROUTE;
        pub const LINK = AF.LINK;
        pub const INET6 = AF.INET6;
        pub const KEY = AF.KEY;
        pub const NCA = AF.NCA;
        pub const POLICY = AF.POLICY;
        pub const TRILL = AF.TRILL;
        pub const PACKET = AF.PACKET;
        pub const LX_NETLINK = AF.LX_NETLINK;
        pub const MAX = AF.MAX;
    },
    .netbsd => struct {
        pub const UNSPEC = AF.UNSPEC;
        pub const LOCAL = AF.LOCAL;
        pub const UNIX = PF.LOCAL;
        pub const INET = AF.INET;
        pub const IMPLINK = AF.IMPLINK;
        pub const PUP = AF.PUP;
        pub const CHAOS = AF.CHAOS;
        pub const NS = AF.NS;
        pub const ISO = AF.ISO;
        pub const OSI = AF.ISO;
        pub const ECMA = AF.ECMA;
        pub const DATAKIT = AF.DATAKIT;
        pub const CCITT = AF.CCITT;
        pub const SNA = AF.SNA;
        pub const DECnet = AF.DECnet;
        pub const DLI = AF.DLI;
        pub const LAT = AF.LAT;
        pub const HYLINK = AF.HYLINK;
        pub const APPLETALK = AF.APPLETALK;
        pub const OROUTE = AF.OROUTE;
        pub const LINK = AF.LINK;
        pub const COIP = AF.COIP;
        pub const CNT = AF.CNT;
        pub const INET6 = AF.INET6;
        pub const IPX = AF.IPX;
        pub const ISDN = AF.ISDN;
        pub const E164 = AF.E164;
        pub const NATM = AF.NATM;
        pub const ARP = AF.ARP;
        pub const BLUETOOTH = AF.BLUETOOTH;
        pub const MPLS = AF.MPLS;
        pub const ROUTE = AF.ROUTE;
        pub const CAN = AF.CAN;
        pub const ETHER = AF.ETHER;
        pub const MAX = AF.MAX;
    },
    .dragonfly => struct {
        pub const INET6 = AF.INET6;
        pub const IMPLINK = AF.IMPLINK;
        pub const ROUTE = AF.ROUTE;
        pub const ISO = AF.ISO;
        pub const PIP = AF.pseudo_PIP;
        pub const CHAOS = AF.CHAOS;
        pub const DATAKIT = AF.DATAKIT;
        pub const INET = AF.INET;
        pub const APPLETALK = AF.APPLETALK;
        pub const SIP = AF.SIP;
        pub const OSI = AF.ISO;
        pub const CNT = AF.CNT;
        pub const LINK = AF.LINK;
        pub const HYLINK = AF.HYLINK;
        pub const MAX = AF.MAX;
        pub const KEY = AF.pseudo_KEY;
        pub const PUP = AF.PUP;
        pub const COIP = AF.COIP;
        pub const SNA = AF.SNA;
        pub const LOCAL = AF.LOCAL;
        pub const NETBIOS = AF.NETBIOS;
        pub const NATM = AF.NATM;
        pub const BLUETOOTH = AF.BLUETOOTH;
        pub const UNSPEC = AF.UNSPEC;
        pub const NETGRAPH = AF.NETGRAPH;
        pub const ECMA = AF.ECMA;
        pub const IPX = AF.IPX;
        pub const DLI = AF.DLI;
        pub const ATM = AF.ATM;
        pub const CCITT = AF.CCITT;
        pub const ISDN = AF.ISDN;
        pub const RTIP = AF.pseudo_RTIP;
        pub const LAT = AF.LAT;
        pub const UNIX = PF.LOCAL;
        pub const XTP = AF.pseudo_XTP;
        pub const DECnet = AF.DECnet;
    },
    .haiku => struct {
        pub const UNSPEC = AF.UNSPEC;
        pub const INET = AF.INET;
        pub const ROUTE = AF.ROUTE;
        pub const LINK = AF.LINK;
        pub const INET6 = AF.INET6;
        pub const LOCAL = AF.LOCAL;
        pub const UNIX = AF.UNIX;
        pub const BLUETOOTH = AF.BLUETOOTH;
    },
    .openbsd => struct {
        pub const UNSPEC = AF.UNSPEC;
        pub const LOCAL = AF.LOCAL;
        pub const UNIX = AF.UNIX;
        pub const INET = AF.INET;
        pub const APPLETALK = AF.APPLETALK;
        pub const INET6 = AF.INET6;
        pub const DECnet = AF.DECnet;
        pub const KEY = AF.KEY;
        pub const ROUTE = AF.ROUTE;
        pub const SNA = AF.SNA;
        pub const MPLS = AF.MPLS;
        pub const BLUETOOTH = AF.BLUETOOTH;
        pub const ISDN = AF.ISDN;
        pub const MAX = AF.MAX;
    },
    else => void,
};
pub const DT = switch (native_os) {
    .linux => linux.DT,
    .netbsd, .freebsd, .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const UNKNOWN = 0;
        pub const FIFO = 1;
        pub const CHR = 2;
        pub const DIR = 4;
        pub const BLK = 6;
        pub const REG = 8;
        pub const LNK = 10;
        pub const SOCK = 12;
        pub const WHT = 14;
    },
    .dragonfly => struct {
        pub const UNKNOWN = 0;
        pub const FIFO = 1;
        pub const CHR = 2;
        pub const DIR = 4;
        pub const BLK = 6;
        pub const REG = 8;
        pub const LNK = 10;
        pub const SOCK = 12;
        pub const WHT = 14;
        pub const DBF = 15;
    },
    .openbsd => struct {
        pub const UNKNOWN = 0;
        pub const FIFO = 1;
        pub const CHR = 2;
        pub const DIR = 4;
        pub const BLK = 6;
        pub const REG = 8;
        pub const LNK = 10;
        pub const SOCK = 12;
        pub const WHT = 14; // XXX
    },
    else => void,
};
pub const MSG = switch (native_os) {
    .linux => linux.MSG,
    .emscripten => emscripten.MSG,
    .windows => ws2_32.MSG,
    .haiku => struct {
        pub const OOB = 0x0001;
        pub const PEEK = 0x0002;
        pub const DONTROUTE = 0x0004;
        pub const EOR = 0x0008;
        pub const TRUNC = 0x0010;
        pub const CTRUNC = 0x0020;
        pub const WAITALL = 0x0040;
        pub const DONTWAIT = 0x0080;
        pub const BCAST = 0x0100;
        pub const MCAST = 0x0200;
        pub const EOF = 0x0400;
        pub const NOSIGNAL = 0x0800;
    },
    else => void,
};
pub const SOCK = switch (native_os) {
    .linux => linux.SOCK,
    .emscripten => emscripten.SOCK,
    .windows => ws2_32.SOCK,
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const STREAM = 1;
        pub const DGRAM = 2;
        pub const RAW = 3;
        pub const RDM = 4;
        pub const SEQPACKET = 5;
        pub const MAXADDRLEN = 255;

        /// Not actually supported by Darwin, but Zig supplies a shim.
        /// This numerical value is not ABI-stable. It need only not conflict
        /// with any other `SOCK` bits.
        pub const CLOEXEC = 1 << 15;
        /// Not actually supported by Darwin, but Zig supplies a shim.
        /// This numerical value is not ABI-stable. It need only not conflict
        /// with any other `SOCK` bits.
        pub const NONBLOCK = 1 << 16;
    },
    .freebsd => struct {
        pub const STREAM = 1;
        pub const DGRAM = 2;
        pub const RAW = 3;
        pub const RDM = 4;
        pub const SEQPACKET = 5;

        pub const CLOEXEC = 0x10000000;
        pub const NONBLOCK = 0x20000000;
    },
    .solaris, .illumos => struct {
        /// Datagram.
        pub const DGRAM = 1;
        /// STREAM.
        pub const STREAM = 2;
        /// Raw-protocol interface.
        pub const RAW = 4;
        /// Reliably-delivered message.
        pub const RDM = 5;
        /// Sequenced packed stream.
        pub const SEQPACKET = 6;

        pub const NONBLOCK = 0x100000;
        pub const NDELAY = 0x200000;
        pub const CLOEXEC = 0x080000;
    },
    .netbsd => struct {
        pub const STREAM = 1;
        pub const DGRAM = 2;
        pub const RAW = 3;
        pub const RDM = 4;
        pub const SEQPACKET = 5;
        pub const CONN_DGRAM = 6;
        pub const DCCP = CONN_DGRAM;

        pub const CLOEXEC = 0x10000000;
        pub const NONBLOCK = 0x20000000;
        pub const NOSIGPIPE = 0x40000000;
        pub const FLAGS_MASK = 0xf0000000;
    },
    .dragonfly => struct {
        pub const STREAM = 1;
        pub const DGRAM = 2;
        pub const RAW = 3;
        pub const RDM = 4;
        pub const SEQPACKET = 5;
        pub const MAXADDRLEN = 255;
        pub const CLOEXEC = 0x10000000;
        pub const NONBLOCK = 0x20000000;
    },
    .haiku => struct {
        pub const STREAM = 1;
        pub const DGRAM = 2;
        pub const RAW = 3;
        pub const SEQPACKET = 5;
        pub const MISC = 255;
    },
    .openbsd => struct {
        pub const STREAM = 1;
        pub const DGRAM = 2;
        pub const RAW = 3;
        pub const RDM = 4;
        pub const SEQPACKET = 5;

        pub const CLOEXEC = 0x8000;
        pub const NONBLOCK = 0x4000;
    },
    else => void,
};
pub const TCP = switch (native_os) {
    .linux => linux.TCP,
    .emscripten => emscripten.TCP,
    .windows => ws2_32.TCP,
    else => void,
};
pub const IPPROTO = switch (native_os) {
    .linux, .emscripten => linux.IPPROTO,
    .windows => ws2_32.IPPROTO,
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const ICMP = 1;
        pub const ICMPV6 = 58;
        pub const TCP = 6;
        pub const UDP = 17;
        pub const IP = 0;
        pub const IPV6 = 41;
    },
    .freebsd => struct {
        /// dummy for IP
        pub const IP = 0;
        /// control message protocol
        pub const ICMP = 1;
        /// tcp
        pub const TCP = 6;
        /// user datagram protocol
        pub const UDP = 17;
        /// IP6 header
        pub const IPV6 = 41;
        /// raw IP packet
        pub const RAW = 255;
        /// IP6 hop-by-hop options
        pub const HOPOPTS = 0;
        /// group mgmt protocol
        pub const IGMP = 2;
        /// gateway^2 (deprecated)
        pub const GGP = 3;
        /// IPv4 encapsulation
        pub const IPV4 = 4;
        /// for compatibility
        pub const IPIP = IPV4;
        /// Stream protocol II
        pub const ST = 7;
        /// exterior gateway protocol
        pub const EGP = 8;
        /// private interior gateway
        pub const PIGP = 9;
        /// BBN RCC Monitoring
        pub const RCCMON = 10;
        /// network voice protocol
        pub const NVPII = 11;
        /// pup
        pub const PUP = 12;
        /// Argus
        pub const ARGUS = 13;
        /// EMCON
        pub const EMCON = 14;
        /// Cross Net Debugger
        pub const XNET = 15;
        /// Chaos
        pub const CHAOS = 16;
        /// Multiplexing
        pub const MUX = 18;
        /// DCN Measurement Subsystems
        pub const MEAS = 19;
        /// Host Monitoring
        pub const HMP = 20;
        /// Packet Radio Measurement
        pub const PRM = 21;
        /// xns idp
        pub const IDP = 22;
        /// Trunk-1
        pub const TRUNK1 = 23;
        /// Trunk-2
        pub const TRUNK2 = 24;
        /// Leaf-1
        pub const LEAF1 = 25;
        /// Leaf-2
        pub const LEAF2 = 26;
        /// Reliable Data
        pub const RDP = 27;
        /// Reliable Transaction
        pub const IRTP = 28;
        /// tp-4 w/ class negotiation
        pub const TP = 29;
        /// Bulk Data Transfer
        pub const BLT = 30;
        /// Network Services
        pub const NSP = 31;
        /// Merit Internodal
        pub const INP = 32;
        /// Datagram Congestion Control Protocol
        pub const DCCP = 33;
        /// Third Party Connect
        pub const @"3PC" = 34;
        /// InterDomain Policy Routing
        pub const IDPR = 35;
        /// XTP
        pub const XTP = 36;
        /// Datagram Delivery
        pub const DDP = 37;
        /// Control Message Transport
        pub const CMTP = 38;
        /// TP++ Transport
        pub const TPXX = 39;
        /// IL transport protocol
        pub const IL = 40;
        /// Source Demand Routing
        pub const SDRP = 42;
        /// IP6 routing header
        pub const ROUTING = 43;
        /// IP6 fragmentation header
        pub const FRAGMENT = 44;
        /// InterDomain Routing
        pub const IDRP = 45;
        /// resource reservation
        pub const RSVP = 46;
        /// General Routing Encap.
        pub const GRE = 47;
        /// Mobile Host Routing
        pub const MHRP = 48;
        /// BHA
        pub const BHA = 49;
        /// IP6 Encap Sec. Payload
        pub const ESP = 50;
        /// IP6 Auth Header
        pub const AH = 51;
        /// Integ. Net Layer Security
        pub const INLSP = 52;
        /// IP with encryption
        pub const SWIPE = 53;
        /// Next Hop Resolution
        pub const NHRP = 54;
        /// IP Mobility
        pub const MOBILE = 55;
        /// Transport Layer Security
        pub const TLSP = 56;
        /// SKIP
        pub const SKIP = 57;
        /// ICMP6
        pub const ICMPV6 = 58;
        /// IP6 no next header
        pub const NONE = 59;
        /// IP6 destination option
        pub const DSTOPTS = 60;
        /// any host internal protocol
        pub const AHIP = 61;
        /// CFTP
        pub const CFTP = 62;
        /// "hello" routing protocol
        pub const HELLO = 63;
        /// SATNET/Backroom EXPAK
        pub const SATEXPAK = 64;
        /// Kryptolan
        pub const KRYPTOLAN = 65;
        /// Remote Virtual Disk
        pub const RVD = 66;
        /// Pluribus Packet Core
        pub const IPPC = 67;
        /// Any distributed FS
        pub const ADFS = 68;
        /// Satnet Monitoring
        pub const SATMON = 69;
        /// VISA Protocol
        pub const VISA = 70;
        /// Packet Core Utility
        pub const IPCV = 71;
        /// Comp. Prot. Net. Executive
        pub const CPNX = 72;
        /// Comp. Prot. HeartBeat
        pub const CPHB = 73;
        /// Wang Span Network
        pub const WSN = 74;
        /// Packet Video Protocol
        pub const PVP = 75;
        /// BackRoom SATNET Monitoring
        pub const BRSATMON = 76;
        /// Sun net disk proto (temp.)
        pub const ND = 77;
        /// WIDEBAND Monitoring
        pub const WBMON = 78;
        /// WIDEBAND EXPAK
        pub const WBEXPAK = 79;
        /// ISO cnlp
        pub const EON = 80;
        /// VMTP
        pub const VMTP = 81;
        /// Secure VMTP
        pub const SVMTP = 82;
        /// Banyon VINES
        pub const VINES = 83;
        /// TTP
        pub const TTP = 84;
        /// NSFNET-IGP
        pub const IGP = 85;
        /// dissimilar gateway prot.
        pub const DGP = 86;
        /// TCF
        pub const TCF = 87;
        /// Cisco/GXS IGRP
        pub const IGRP = 88;
        /// OSPFIGP
        pub const OSPFIGP = 89;
        /// Strite RPC protocol
        pub const SRPC = 90;
        /// Locus Address Resoloution
        pub const LARP = 91;
        /// Multicast Transport
        pub const MTP = 92;
        /// AX.25 Frames
        pub const AX25 = 93;
        /// IP encapsulated in IP
        pub const IPEIP = 94;
        /// Mobile Int.ing control
        pub const MICP = 95;
        /// Semaphore Comm. security
        pub const SCCSP = 96;
        /// Ethernet IP encapsulation
        pub const ETHERIP = 97;
        /// encapsulation header
        pub const ENCAP = 98;
        /// any private encr. scheme
        pub const APES = 99;
        /// GMTP
        pub const GMTP = 100;
        /// payload compression (IPComp)
        pub const IPCOMP = 108;
        /// SCTP
        pub const SCTP = 132;
        /// IPv6 Mobility Header
        pub const MH = 135;
        /// UDP-Lite
        pub const UDPLITE = 136;
        /// IP6 Host Identity Protocol
        pub const HIP = 139;
        /// IP6 Shim6 Protocol
        pub const SHIM6 = 140;
        /// Protocol Independent Mcast
        pub const PIM = 103;
        /// CARP
        pub const CARP = 112;
        /// PGM
        pub const PGM = 113;
        /// MPLS-in-IP
        pub const MPLS = 137;
        /// PFSYNC
        pub const PFSYNC = 240;
        /// Reserved
        pub const RESERVED_253 = 253;
        /// Reserved
        pub const RESERVED_254 = 254;
    },
    .solaris, .illumos => struct {
        /// dummy for IP
        pub const IP = 0;
        /// Hop by hop header for IPv6
        pub const HOPOPTS = 0;
        /// control message protocol
        pub const ICMP = 1;
        /// group control protocol
        pub const IGMP = 2;
        /// gateway^2 (deprecated)
        pub const GGP = 3;
        /// IP in IP encapsulation
        pub const ENCAP = 4;
        /// tcp
        pub const TCP = 6;
        /// exterior gateway protocol
        pub const EGP = 8;
        /// pup
        pub const PUP = 12;
        /// user datagram protocol
        pub const UDP = 17;
        /// xns idp
        pub const IDP = 22;
        /// IPv6 encapsulated in IP
        pub const IPV6 = 41;
        /// Routing header for IPv6
        pub const ROUTING = 43;
        /// Fragment header for IPv6
        pub const FRAGMENT = 44;
        /// rsvp
        pub const RSVP = 46;
        /// IPsec Encap. Sec. Payload
        pub const ESP = 50;
        /// IPsec Authentication Hdr.
        pub const AH = 51;
        /// ICMP for IPv6
        pub const ICMPV6 = 58;
        /// No next header for IPv6
        pub const NONE = 59;
        /// Destination options
        pub const DSTOPTS = 60;
        /// "hello" routing protocol
        pub const HELLO = 63;
        /// UNOFFICIAL net disk proto
        pub const ND = 77;
        /// ISO clnp
        pub const EON = 80;
        /// OSPF
        pub const OSPF = 89;
        /// PIM routing protocol
        pub const PIM = 103;
        /// Stream Control
        pub const SCTP = 132;
        /// raw IP packet
        pub const RAW = 255;
        /// Sockets Direct Protocol
        pub const PROTO_SDP = 257;
    },
    .netbsd => struct {
        /// dummy for IP
        pub const IP = 0;
        /// IP6 hop-by-hop options
        pub const HOPOPTS = 0;
        /// control message protocol
        pub const ICMP = 1;
        /// group mgmt protocol
        pub const IGMP = 2;
        /// gateway^2 (deprecated)
        pub const GGP = 3;
        /// IP header
        pub const IPV4 = 4;
        /// IP inside IP
        pub const IPIP = 4;
        /// tcp
        pub const TCP = 6;
        /// exterior gateway protocol
        pub const EGP = 8;
        /// pup
        pub const PUP = 12;
        /// user datagram protocol
        pub const UDP = 17;
        /// xns idp
        pub const IDP = 22;
        /// tp-4 w/ class negotiation
        pub const TP = 29;
        /// DCCP
        pub const DCCP = 33;
        /// IP6 header
        pub const IPV6 = 41;
        /// IP6 routing header
        pub const ROUTING = 43;
        /// IP6 fragmentation header
        pub const FRAGMENT = 44;
        /// resource reservation
        pub const RSVP = 46;
        /// GRE encaps RFC 1701
        pub const GRE = 47;
        /// encap. security payload
        pub const ESP = 50;
        /// authentication header
        pub const AH = 51;
        /// IP Mobility RFC 2004
        pub const MOBILE = 55;
        /// IPv6 ICMP
        pub const IPV6_ICMP = 58;
        /// ICMP6
        pub const ICMPV6 = 58;
        /// IP6 no next header
        pub const NONE = 59;
        /// IP6 destination option
        pub const DSTOPTS = 60;
        /// ISO cnlp
        pub const EON = 80;
        /// Ethernet-in-IP
        pub const ETHERIP = 97;
        /// encapsulation header
        pub const ENCAP = 98;
        /// Protocol indep. multicast
        pub const PIM = 103;
        /// IP Payload Comp. Protocol
        pub const IPCOMP = 108;
        /// VRRP RFC 2338
        pub const VRRP = 112;
        /// Common Address Resolution Protocol
        pub const CARP = 112;
        /// L2TPv3
        pub const L2TP = 115;
        /// SCTP
        pub const SCTP = 132;
        /// PFSYNC
        pub const PFSYNC = 240;
        /// raw IP packet
        pub const RAW = 255;
    },
    .dragonfly => struct {
        pub const IP = 0;
        pub const ICMP = 1;
        pub const TCP = 6;
        pub const UDP = 17;
        pub const IPV6 = 41;
        pub const RAW = 255;
        pub const HOPOPTS = 0;
        pub const IGMP = 2;
        pub const GGP = 3;
        pub const IPV4 = 4;
        pub const IPIP = IPV4;
        pub const ST = 7;
        pub const EGP = 8;
        pub const PIGP = 9;
        pub const RCCMON = 10;
        pub const NVPII = 11;
        pub const PUP = 12;
        pub const ARGUS = 13;
        pub const EMCON = 14;
        pub const XNET = 15;
        pub const CHAOS = 16;
        pub const MUX = 18;
        pub const MEAS = 19;
        pub const HMP = 20;
        pub const PRM = 21;
        pub const IDP = 22;
        pub const TRUNK1 = 23;
        pub const TRUNK2 = 24;
        pub const LEAF1 = 25;
        pub const LEAF2 = 26;
        pub const RDP = 27;
        pub const IRTP = 28;
        pub const TP = 29;
        pub const BLT = 30;
        pub const NSP = 31;
        pub const INP = 32;
        pub const SEP = 33;
        pub const @"3PC" = 34;
        pub const IDPR = 35;
        pub const XTP = 36;
        pub const DDP = 37;
        pub const CMTP = 38;
        pub const TPXX = 39;
        pub const IL = 40;
        pub const SDRP = 42;
        pub const ROUTING = 43;
        pub const FRAGMENT = 44;
        pub const IDRP = 45;
        pub const RSVP = 46;
        pub const GRE = 47;
        pub const MHRP = 48;
        pub const BHA = 49;
        pub const ESP = 50;
        pub const AH = 51;
        pub const INLSP = 52;
        pub const SWIPE = 53;
        pub const NHRP = 54;
        pub const MOBILE = 55;
        pub const TLSP = 56;
        pub const SKIP = 57;
        pub const ICMPV6 = 58;
        pub const NONE = 59;
        pub const DSTOPTS = 60;
        pub const AHIP = 61;
        pub const CFTP = 62;
        pub const HELLO = 63;
        pub const SATEXPAK = 64;
        pub const KRYPTOLAN = 65;
        pub const RVD = 66;
        pub const IPPC = 67;
        pub const ADFS = 68;
        pub const SATMON = 69;
        pub const VISA = 70;
        pub const IPCV = 71;
        pub const CPNX = 72;
        pub const CPHB = 73;
        pub const WSN = 74;
        pub const PVP = 75;
        pub const BRSATMON = 76;
        pub const ND = 77;
        pub const WBMON = 78;
        pub const WBEXPAK = 79;
        pub const EON = 80;
        pub const VMTP = 81;
        pub const SVMTP = 82;
        pub const VINES = 83;
        pub const TTP = 84;
        pub const IGP = 85;
        pub const DGP = 86;
        pub const TCF = 87;
        pub const IGRP = 88;
        pub const OSPFIGP = 89;
        pub const SRPC = 90;
        pub const LARP = 91;
        pub const MTP = 92;
        pub const AX25 = 93;
        pub const IPEIP = 94;
        pub const MICP = 95;
        pub const SCCSP = 96;
        pub const ETHERIP = 97;
        pub const ENCAP = 98;
        pub const APES = 99;
        pub const GMTP = 100;
        pub const IPCOMP = 108;
        pub const PIM = 103;
        pub const CARP = 112;
        pub const PGM = 113;
        pub const PFSYNC = 240;
        pub const DIVERT = 254;
        pub const MAX = 256;
        pub const DONE = 257;
        pub const UNKNOWN = 258;
    },
    .haiku => struct {
        pub const IP = 0;
        pub const HOPOPTS = 0;
        pub const ICMP = 1;
        pub const IGMP = 2;
        pub const TCP = 6;
        pub const UDP = 17;
        pub const IPV6 = 41;
        pub const ROUTING = 43;
        pub const FRAGMENT = 44;
        pub const ESP = 50;
        pub const AH = 51;
        pub const ICMPV6 = 58;
        pub const NONE = 59;
        pub const DSTOPTS = 60;
        pub const ETHERIP = 97;
        pub const RAW = 255;
        pub const MAX = 256;
    },
    .openbsd => struct {
        /// dummy for IP
        pub const IP = 0;
        /// IP6 hop-by-hop options
        pub const HOPOPTS = IP;
        /// control message protocol
        pub const ICMP = 1;
        /// group mgmt protocol
        pub const IGMP = 2;
        /// gateway^2 (deprecated)
        pub const GGP = 3;
        /// IP header
        pub const IPV4 = IPIP;
        /// IP inside IP
        pub const IPIP = 4;
        /// tcp
        pub const TCP = 6;
        /// exterior gateway protocol
        pub const EGP = 8;
        /// pup
        pub const PUP = 12;
        /// user datagram protocol
        pub const UDP = 17;
        /// xns idp
        pub const IDP = 22;
        /// tp-4 w/ class negotiation
        pub const TP = 29;
        /// IP6 header
        pub const IPV6 = 41;
        /// IP6 routing header
        pub const ROUTING = 43;
        /// IP6 fragmentation header
        pub const FRAGMENT = 44;
        /// resource reservation
        pub const RSVP = 46;
        /// GRE encaps RFC 1701
        pub const GRE = 47;
        /// encap. security payload
        pub const ESP = 50;
        /// authentication header
        pub const AH = 51;
        /// IP Mobility RFC 2004
        pub const MOBILE = 55;
        /// IPv6 ICMP
        pub const IPV6_ICMP = 58;
        /// ICMP6
        pub const ICMPV6 = 58;
        /// IP6 no next header
        pub const NONE = 59;
        /// IP6 destination option
        pub const DSTOPTS = 60;
        /// ISO cnlp
        pub const EON = 80;
        /// Ethernet-in-IP
        pub const ETHERIP = 97;
        /// encapsulation header
        pub const ENCAP = 98;
        /// Protocol indep. multicast
        pub const PIM = 103;
        /// IP Payload Comp. Protocol
        pub const IPCOMP = 108;
        /// VRRP RFC 2338
        pub const VRRP = 112;
        /// Common Address Resolution Protocol
        pub const CARP = 112;
        /// PFSYNC
        pub const PFSYNC = 240;
        /// raw IP packet
        pub const RAW = 255;
    },
    else => void,
};
pub const SOL = switch (native_os) {
    .linux => linux.SOL,
    .emscripten => emscripten.SOL,
    .windows => ws2_32.SOL,
    .openbsd, .haiku, .dragonfly, .netbsd, .freebsd, .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const SOCKET = 0xffff;
    },
    .solaris, .illumos => struct {
        pub const SOCKET = 0xffff;
        pub const ROUTE = 0xfffe;
        pub const PACKET = 0xfffd;
        pub const FILTER = 0xfffc;
    },
    else => void,
};
pub const SO = switch (native_os) {
    .linux => linux.SO,
    .emscripten => emscripten.SO,
    .windows => ws2_32.SO,
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const DEBUG = 0x0001;
        pub const ACCEPTCONN = 0x0002;
        pub const REUSEADDR = 0x0004;
        pub const KEEPALIVE = 0x0008;
        pub const DONTROUTE = 0x0010;
        pub const BROADCAST = 0x0020;
        pub const USELOOPBACK = 0x0040;
        pub const LINGER = 0x1080;
        pub const OOBINLINE = 0x0100;
        pub const REUSEPORT = 0x0200;
        pub const ACCEPTFILTER = 0x1000;
        pub const SNDBUF = 0x1001;
        pub const RCVBUF = 0x1002;
        pub const SNDLOWAT = 0x1003;
        pub const RCVLOWAT = 0x1004;
        pub const SNDTIMEO = 0x1005;
        pub const RCVTIMEO = 0x1006;
        pub const ERROR = 0x1007;
        pub const TYPE = 0x1008;

        pub const NREAD = 0x1020;
        pub const NKE = 0x1021;
        pub const NOSIGPIPE = 0x1022;
        pub const NOADDRERR = 0x1023;
        pub const NWRITE = 0x1024;
        pub const REUSESHAREUID = 0x1025;
    },
    .freebsd => struct {
        pub const DEBUG = 0x00000001;
        pub const ACCEPTCONN = 0x00000002;
        pub const REUSEADDR = 0x00000004;
        pub const KEEPALIVE = 0x00000008;
        pub const DONTROUTE = 0x00000010;
        pub const BROADCAST = 0x00000020;
        pub const USELOOPBACK = 0x00000040;
        pub const LINGER = 0x00000080;
        pub const OOBINLINE = 0x00000100;
        pub const REUSEPORT = 0x00000200;
        pub const TIMESTAMP = 0x00000400;
        pub const NOSIGPIPE = 0x00000800;
        pub const ACCEPTFILTER = 0x00001000;
        pub const BINTIME = 0x00002000;
        pub const NO_OFFLOAD = 0x00004000;
        pub const NO_DDP = 0x00008000;
        pub const REUSEPORT_LB = 0x00010000;

        pub const SNDBUF = 0x1001;
        pub const RCVBUF = 0x1002;
        pub const SNDLOWAT = 0x1003;
        pub const RCVLOWAT = 0x1004;
        pub const SNDTIMEO = 0x1005;
        pub const RCVTIMEO = 0x1006;
        pub const ERROR = 0x1007;
        pub const TYPE = 0x1008;
        pub const LABEL = 0x1009;
        pub const PEERLABEL = 0x1010;
        pub const LISTENQLIMIT = 0x1011;
        pub const LISTENQLEN = 0x1012;
        pub const LISTENINCQLEN = 0x1013;
        pub const SETFIB = 0x1014;
        pub const USER_COOKIE = 0x1015;
        pub const PROTOCOL = 0x1016;
        pub const PROTOTYPE = PROTOCOL;
        pub const TS_CLOCK = 0x1017;
        pub const MAX_PACING_RATE = 0x1018;
        pub const DOMAIN = 0x1019;
    },
    .solaris, .illumos => struct {
        pub const DEBUG = 0x0001;
        pub const ACCEPTCONN = 0x0002;
        pub const REUSEADDR = 0x0004;
        pub const KEEPALIVE = 0x0008;
        pub const DONTROUTE = 0x0010;
        pub const BROADCAST = 0x0020;
        pub const USELOOPBACK = 0x0040;
        pub const LINGER = 0x0080;
        pub const OOBINLINE = 0x0100;
        pub const DGRAM_ERRIND = 0x0200;
        pub const RECVUCRED = 0x0400;

        pub const SNDBUF = 0x1001;
        pub const RCVBUF = 0x1002;
        pub const SNDLOWAT = 0x1003;
        pub const RCVLOWAT = 0x1004;
        pub const SNDTIMEO = 0x1005;
        pub const RCVTIMEO = 0x1006;
        pub const ERROR = 0x1007;
        pub const TYPE = 0x1008;
        pub const PROTOTYPE = 0x1009;
        pub const ANON_MLP = 0x100a;
        pub const MAC_EXEMPT = 0x100b;
        pub const DOMAIN = 0x100c;
        pub const RCVPSH = 0x100d;

        pub const SECATTR = 0x1011;
        pub const TIMESTAMP = 0x1013;
        pub const ALLZONES = 0x1014;
        pub const EXCLBIND = 0x1015;
        pub const MAC_IMPLICIT = 0x1016;
        pub const VRRP = 0x1017;
    },
    .netbsd => struct {
        pub const DEBUG = 0x0001;
        pub const ACCEPTCONN = 0x0002;
        pub const REUSEADDR = 0x0004;
        pub const KEEPALIVE = 0x0008;
        pub const DONTROUTE = 0x0010;
        pub const BROADCAST = 0x0020;
        pub const USELOOPBACK = 0x0040;
        pub const LINGER = 0x0080;
        pub const OOBINLINE = 0x0100;
        pub const REUSEPORT = 0x0200;
        pub const NOSIGPIPE = 0x0800;
        pub const ACCEPTFILTER = 0x1000;
        pub const TIMESTAMP = 0x2000;
        pub const RERROR = 0x4000;

        pub const SNDBUF = 0x1001;
        pub const RCVBUF = 0x1002;
        pub const SNDLOWAT = 0x1003;
        pub const RCVLOWAT = 0x1004;
        pub const ERROR = 0x1007;
        pub const TYPE = 0x1008;
        pub const OVERFLOWED = 0x1009;

        pub const NOHEADER = 0x100a;
        pub const SNDTIMEO = 0x100b;
        pub const RCVTIMEO = 0x100c;
    },
    .dragonfly => struct {
        pub const DEBUG = 0x0001;
        pub const ACCEPTCONN = 0x0002;
        pub const REUSEADDR = 0x0004;
        pub const KEEPALIVE = 0x0008;
        pub const DONTROUTE = 0x0010;
        pub const BROADCAST = 0x0020;
        pub const USELOOPBACK = 0x0040;
        pub const LINGER = 0x0080;
        pub const OOBINLINE = 0x0100;
        pub const REUSEPORT = 0x0200;
        pub const TIMESTAMP = 0x0400;
        pub const NOSIGPIPE = 0x0800;
        pub const ACCEPTFILTER = 0x1000;
        pub const RERROR = 0x2000;
        pub const PASSCRED = 0x4000;

        pub const SNDBUF = 0x1001;
        pub const RCVBUF = 0x1002;
        pub const SNDLOWAT = 0x1003;
        pub const RCVLOWAT = 0x1004;
        pub const SNDTIMEO = 0x1005;
        pub const RCVTIMEO = 0x1006;
        pub const ERROR = 0x1007;
        pub const TYPE = 0x1008;
        pub const SNDSPACE = 0x100a;
        pub const CPUHINT = 0x1030;
    },
    .haiku => struct {
        pub const ACCEPTCONN = 0x00000001;
        pub const BROADCAST = 0x00000002;
        pub const DEBUG = 0x00000004;
        pub const DONTROUTE = 0x00000008;
        pub const KEEPALIVE = 0x00000010;
        pub const OOBINLINE = 0x00000020;
        pub const REUSEADDR = 0x00000040;
        pub const REUSEPORT = 0x00000080;
        pub const USELOOPBACK = 0x00000100;
        pub const LINGER = 0x00000200;

        pub const SNDBUF = 0x40000001;
        pub const SNDLOWAT = 0x40000002;
        pub const SNDTIMEO = 0x40000003;
        pub const RCVBUF = 0x40000004;
        pub const RCVLOWAT = 0x40000005;
        pub const RCVTIMEO = 0x40000006;
        pub const ERROR = 0x40000007;
        pub const TYPE = 0x40000008;
        pub const NONBLOCK = 0x40000009;
        pub const BINDTODEVICE = 0x4000000a;
        pub const PEERCRED = 0x4000000b;
    },
    .openbsd => struct {
        pub const DEBUG = 0x0001;
        pub const ACCEPTCONN = 0x0002;
        pub const REUSEADDR = 0x0004;
        pub const KEEPALIVE = 0x0008;
        pub const DONTROUTE = 0x0010;
        pub const BROADCAST = 0x0020;
        pub const USELOOPBACK = 0x0040;
        pub const LINGER = 0x0080;
        pub const OOBINLINE = 0x0100;
        pub const REUSEPORT = 0x0200;
        pub const TIMESTAMP = 0x0800;
        pub const BINDANY = 0x1000;
        pub const ZEROIZE = 0x2000;
        pub const SNDBUF = 0x1001;
        pub const RCVBUF = 0x1002;
        pub const SNDLOWAT = 0x1003;
        pub const RCVLOWAT = 0x1004;
        pub const SNDTIMEO = 0x1005;
        pub const RCVTIMEO = 0x1006;
        pub const ERROR = 0x1007;
        pub const TYPE = 0x1008;
        pub const NETPROC = 0x1020;
        pub const RTABLE = 0x1021;
        pub const PEERCRED = 0x1022;
        pub const SPLICE = 0x1023;
        pub const DOMAIN = 0x1024;
        pub const PROTOCOL = 0x1025;
    },
    else => void,
};
pub const SOMAXCONN = switch (native_os) {
    .linux => linux.SOMAXCONN,
    .windows => ws2_32.SOMAXCONN,
    .solaris, .illumos => 128,
    .openbsd => 28,
    else => void,
};
pub const IFNAMESIZE = switch (native_os) {
    .linux => linux.IFNAMESIZE,
    .emscripten => emscripten.IFNAMESIZE,
    .windows => 30,
    .openbsd, .dragonfly, .netbsd, .freebsd, .macos, .ios, .tvos, .watchos, .visionos => 16,
    .solaris, .illumos => 32,
    else => void,
};

pub const stack_t = switch (native_os) {
    .linux => linux.stack_t,
    .emscripten => emscripten.stack_t,
    .freebsd => extern struct {
        /// Signal stack base.
        sp: *anyopaque,
        /// Signal stack length.
        size: usize,
        /// SS_DISABLE and/or SS_ONSTACK.
        flags: i32,
    },
    else => extern struct {
        sp: [*]u8,
        size: isize,
        flags: i32,
    },
};
pub const time_t = switch (native_os) {
    .linux => linux.time_t,
    .emscripten => emscripten.time_t,
    .haiku, .dragonfly => isize,
    else => i64,
};
pub const suseconds_t = switch (native_os) {
    .solaris, .illumos => i64,
    .freebsd, .dragonfly => c_long,
    .netbsd => c_int,
    .haiku => i32,
    else => void,
};

pub const timeval = switch (native_os) {
    .linux => linux.timeval,
    .emscripten => emscripten.timeval,
    .windows => extern struct {
        sec: c_long,
        usec: c_long,
    },
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        sec: c_long,
        usec: i32,
    },
    .dragonfly, .netbsd, .freebsd, .solaris, .illumos => extern struct {
        /// seconds
        sec: time_t,
        /// microseconds
        usec: suseconds_t,
    },
    .openbsd => extern struct {
        sec: time_t,
        usec: c_long,
    },
    else => void,
};
pub const timezone = switch (native_os) {
    .linux => linux.timezone,
    .emscripten => emscripten.timezone,
    .openbsd, .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        minuteswest: i32,
        dsttime: i32,
    },
    else => void,
};

pub const ucontext_t = switch (native_os) {
    .linux => linux.ucontext_t,
    .emscripten => emscripten.ucontext_t,
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        onstack: c_int,
        sigmask: sigset_t,
        stack: stack_t,
        link: ?*ucontext_t,
        mcsize: u64,
        mcontext: *mcontext_t,
        __mcontext_data: mcontext_t,
    },
    .freebsd => extern struct {
        sigmask: sigset_t,
        mcontext: mcontext_t,
        link: ?*ucontext_t,
        stack: stack_t,
        flags: c_int,
        __spare__: [4]c_int,
    },
    .solaris, .illumos => extern struct {
        flags: u64,
        link: ?*ucontext_t,
        sigmask: sigset_t,
        stack: stack_t,
        mcontext: mcontext_t,
        brand_data: [3]?*anyopaque,
        filler: [2]i64,
    },
    .netbsd => extern struct {
        flags: u32,
        link: ?*ucontext_t,
        sigmask: sigset_t,
        stack: stack_t,
        mcontext: mcontext_t,
        __pad: [
            switch (builtin.cpu.arch) {
                .x86 => 4,
                .mips, .mipsel, .mips64, .mips64el => 14,
                .arm, .armeb, .thumb, .thumbeb => 1,
                .sparc, .sparc64 => if (@sizeOf(usize) == 4) 43 else 8,
                else => 0,
            }
        ]u32,
    },
    .dragonfly => extern struct {
        sigmask: sigset_t,
        mcontext: mcontext_t,
        link: ?*ucontext_t,
        stack: stack_t,
        cofunc: ?*fn (?*ucontext_t, ?*anyopaque) void,
        arg: ?*void,
        _spare: [4]c_int,
    },
    .haiku => extern struct {
        link: ?*ucontext_t,
        sigmask: sigset_t,
        stack: stack_t,
        mcontext: mcontext_t,
    },
    .openbsd => openbsd.ucontext_t,
    else => void,
};
pub const mcontext_t = switch (native_os) {
    .linux => linux.mcontext_t,
    .emscripten => emscripten.mcontext_t,
    .macos, .ios, .tvos, .watchos, .visionos => darwin.mcontext_t,
    .freebsd => switch (builtin.cpu.arch) {
        .x86_64 => extern struct {
            onstack: u64,
            rdi: u64,
            rsi: u64,
            rdx: u64,
            rcx: u64,
            r8: u64,
            r9: u64,
            rax: u64,
            rbx: u64,
            rbp: u64,
            r10: u64,
            r11: u64,
            r12: u64,
            r13: u64,
            r14: u64,
            r15: u64,
            trapno: u32,
            fs: u16,
            gs: u16,
            addr: u64,
            flags: u32,
            es: u16,
            ds: u16,
            err: u64,
            rip: u64,
            cs: u64,
            rflags: u64,
            rsp: u64,
            ss: u64,
            len: u64,
            fpformat: u64,
            ownedfp: u64,
            fpstate: [64]u64 align(16),
            fsbase: u64,
            gsbase: u64,
            xfpustate: u64,
            xfpustate_len: u64,
            spare: [4]u64,
        },
        .aarch64 => extern struct {
            gpregs: extern struct {
                x: [30]u64,
                lr: u64,
                sp: u64,
                elr: u64,
                spsr: u32,
                _pad: u32,
            },
            fpregs: extern struct {
                q: [32]u128,
                sr: u32,
                cr: u32,
                flags: u32,
                _pad: u32,
            },
            flags: u32,
            _pad: u32,
            _spare: [8]u64,
        },
        else => struct {},
    },
    .solaris, .illumos => extern struct {
        gregs: [28]u64,
        fpregs: solaris.fpregset_t,
    },
    .netbsd => switch (builtin.cpu.arch) {
        .aarch64 => extern struct {
            gregs: [35]u64,
            fregs: [528]u8 align(16),
            spare: [8]u64,
        },
        .x86_64 => extern struct {
            gregs: [26]u64,
            mc_tlsbase: u64,
            fpregs: [512]u8 align(8),
        },
        else => struct {},
    },
    .dragonfly => dragonfly.mcontext_t,
    .haiku => haiku.mcontext_t,
    else => void,
};

pub const user_desc = switch (native_os) {
    .linux => linux.user_desc,
    else => void,
};
pub const utsname = switch (native_os) {
    .linux => linux.utsname,
    .emscripten => emscripten.utsname,
    .solaris, .illumos => extern struct {
        sysname: [256:0]u8,
        nodename: [256:0]u8,
        release: [256:0]u8,
        version: [256:0]u8,
        machine: [256:0]u8,
        domainname: [256:0]u8,
    },
    else => void,
};
pub const PR = switch (native_os) {
    .linux => linux.PR,
    else => void,
};
pub const _errno = switch (native_os) {
    .linux => switch (native_abi) {
        .android, .androideabi => private.__errno,
        else => private.__errno_location,
    },
    .emscripten => private.__errno_location,
    .wasi, .dragonfly => private.errnoFromThreadLocal,
    .windows => private._errno,
    .macos, .ios, .tvos, .watchos, .visionos, .freebsd => private.__error,
    .solaris, .illumos => private.___errno,
    .openbsd, .netbsd => private.__errno,
    .haiku => haiku._errnop,
    else => {},
};

pub const RTLD = switch (native_os) {
    .linux, .emscripten => packed struct(u32) {
        LAZY: bool = false,
        NOW: bool = false,
        NOLOAD: bool = false,
        _3: u5 = 0,
        GLOBAL: bool = false,
        _9: u3 = 0,
        NODELETE: bool = false,
        _: u19 = 0,
    },
    .dragonfly, .freebsd => packed struct(u32) {
        LAZY: bool = false,
        NOW: bool = false,
        _2: u6 = 0,
        GLOBAL: bool = false,
        TRACE: bool = false,
        _10: u2 = 0,
        NODELETE: bool = false,
        NOLOAD: bool = false,
        _: u18 = 0,
    },
    .haiku => packed struct(u32) {
        NOW: bool = false,
        GLOBAL: bool = false,
        _: u30 = 0,
    },
    .netbsd => packed struct(u32) {
        LAZY: bool = false,
        NOW: bool = false,
        _2: u6 = 0,
        GLOBAL: bool = false,
        LOCAL: bool = false,
        _10: u2 = 0,
        NODELETE: bool = false,
        NOLOAD: bool = false,
        _: u18 = 0,
    },
    .solaris, .illumos => packed struct(u32) {
        LAZY: bool = false,
        NOW: bool = false,
        NOLOAD: bool = false,
        _3: u5 = 0,
        GLOBAL: bool = false,
        PARENT: bool = false,
        GROUP: bool = false,
        WORLD: bool = false,
        NODELETE: bool = false,
        FIRST: bool = false,
        _14: u2 = 0,
        CONFGEN: bool = false,
        _: u15 = 0,
    },
    .openbsd => packed struct(u32) {
        LAZY: bool = false,
        NOW: bool = false,
        _2: u6 = 0,
        GLOBAL: bool = false,
        TRACE: bool = false,
        _: u22 = 0,
    },
    .macos, .ios, .tvos, .watchos, .visionos => packed struct(u32) {
        LAZY: bool = false,
        NOW: bool = false,
        LOCAL: bool = false,
        GLOBAL: bool = false,
        NOLOAD: bool = false,
        _5: u2 = 0,
        NODELETE: bool = false,
        FIRST: bool = false,
        _: u23 = 0,
    },
    else => void,
};

pub const dirent = switch (native_os) {
    .linux, .emscripten => extern struct {
        ino: c_uint,
        off: c_uint,
        reclen: c_ushort,
        type: u8,
        name: [256]u8,
    },
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        ino: u64,
        seekoff: u64,
        reclen: u16,
        namlen: u16,
        type: u8,
        name: [1024]u8,
    },
    .freebsd => extern struct {
        /// File number of entry.
        fileno: ino_t,
        /// Directory offset of entry.
        off: off_t,
        /// Length of this record.
        reclen: u16,
        /// File type, one of DT_.
        type: u8,
        pad0: u8 = 0,
        /// Length of the name member.
        namlen: u16,
        pad1: u16 = 0,
        /// Name of entry.
        name: [255:0]u8,
    },
    .solaris, .illumos => extern struct {
        /// Inode number of entry.
        ino: ino_t,
        /// Offset of this entry on disk.
        off: off_t,
        /// Length of this record.
        reclen: u16,
        /// File name.
        name: [MAXNAMLEN:0]u8,
    },
    .netbsd => extern struct {
        fileno: ino_t,
        reclen: u16,
        namlen: u16,
        type: u8,
        name: [MAXNAMLEN:0]u8,
    },
    .dragonfly => extern struct {
        fileno: c_ulong,
        namlen: u16,
        type: u8,
        unused1: u8,
        unused2: u32,
        name: [256]u8,

        pub fn reclen(self: dirent) u16 {
            return (@offsetOf(dirent, "name") + self.namlen + 1 + 7) & ~@as(u16, 7);
        }
    },
    .openbsd => extern struct {
        fileno: ino_t,
        off: off_t,
        reclen: u16,
        type: u8,
        namlen: u8,
        _: u32 align(1) = 0,
        name: [MAXNAMLEN:0]u8,
    },
    else => void,
};
pub const MAXNAMLEN = switch (native_os) {
    .netbsd, .solaris, .illumos => 511,
    .haiku => NAME_MAX,
    .openbsd => 255,
    else => {},
};
pub const dirent64 = switch (native_os) {
    .linux => extern struct {
        ino: c_ulong,
        off: c_ulong,
        reclen: c_ushort,
        type: u8,
        name: [256]u8,
    },
    else => void,
};

pub const AI = switch (native_os) {
    .linux, .emscripten => linux.AI,
    .dragonfly, .haiku, .freebsd => packed struct(u32) {
        PASSIVE: bool = false,
        CANONNAME: bool = false,
        NUMERICHOST: bool = false,
        NUMERICSERV: bool = false,
        _4: u4 = 0,
        ALL: bool = false,
        V4MAPPED_CFG: bool = false,
        ADDRCONFIG: bool = false,
        V4MAPPED: bool = false,
        _: u20 = 0,
    },
    .netbsd => packed struct(u32) {
        PASSIVE: bool = false,
        CANONNAME: bool = false,
        NUMERICHOST: bool = false,
        NUMERICSERV: bool = false,
        _4: u6 = 0,
        ADDRCONFIG: bool = false,
        _: u21 = 0,
    },
    .solaris, .illumos => packed struct(u32) {
        V4MAPPED: bool = false,
        ALL: bool = false,
        ADDRCONFIG: bool = false,
        PASSIVE: bool = false,
        CANONNAME: bool = false,
        NUMERICHOST: bool = false,
        NUMERICSERV: bool = false,
        _: u25 = 0,
    },
    .openbsd => packed struct(u32) {
        PASSIVE: bool = false,
        CANONNAME: bool = false,
        NUMERICHOST: bool = false,
        _3: u1 = 0,
        NUMERICSERV: bool = false,
        _5: u1 = 0,
        ADDRCONFIG: bool = false,
        _: u25 = 0,
    },
    .macos, .ios, .tvos, .watchos, .visionos => packed struct(u32) {
        PASSIVE: bool = false,
        CANONNAME: bool = false,
        NUMERICHOST: bool = false,
        _3: u9 = 0,
        NUMERICSERV: bool = false,
        _: u19 = 0,
    },
    .windows => ws2_32.AI,
    else => void,
};

pub const NI = switch (native_os) {
    .linux, .emscripten => packed struct(u32) {
        NUMERICHOST: bool = false,
        NUMERICSERV: bool = false,
        NOFQDN: bool = false,
        NAMEREQD: bool = false,
        DGRAM: bool = false,
        _5: u3 = 0,
        NUMERICSCOPE: bool = false,
        _: u23 = 0,
    },
    .solaris, .illumos => packed struct(u32) {
        NOFQDN: bool = false,
        NUMERICHOST: bool = false,
        NAMEREQD: bool = false,
        NUMERICSERV: bool = false,
        DGRAM: bool = false,
        WITHSCOPEID: bool = false,
        NUMERICSCOPE: bool = false,
        _: u25 = 0,
    },
    else => void,
};

pub const EAI = switch (native_os) {
    .linux, .emscripten => enum(c_int) {
        BADFLAGS = -1,
        NONAME = -2,
        AGAIN = -3,
        FAIL = -4,
        FAMILY = -6,
        SOCKTYPE = -7,
        SERVICE = -8,
        MEMORY = -10,
        SYSTEM = -11,
        OVERFLOW = -12,

        NODATA = -5,
        ADDRFAMILY = -9,
        INPROGRESS = -100,
        CANCELED = -101,
        NOTCANCELED = -102,
        ALLDONE = -103,
        INTR = -104,
        IDN_ENCODE = -105,

        _,
    },
    .haiku, .dragonfly, .netbsd, .freebsd, .macos, .ios, .tvos, .watchos, .visionos => enum(c_int) {
        /// address family for hostname not supported
        ADDRFAMILY = 1,
        /// temporary failure in name resolution
        AGAIN = 2,
        /// invalid value for ai_flags
        BADFLAGS = 3,
        /// non-recoverable failure in name resolution
        FAIL = 4,
        /// ai_family not supported
        FAMILY = 5,
        /// memory allocation failure
        MEMORY = 6,
        /// no address associated with hostname
        NODATA = 7,
        /// hostname nor servname provided, or not known
        NONAME = 8,
        /// servname not supported for ai_socktype
        SERVICE = 9,
        /// ai_socktype not supported
        SOCKTYPE = 10,
        /// system error returned in errno
        SYSTEM = 11,
        /// invalid value for hints
        BADHINTS = 12,
        /// resolved protocol is unknown
        PROTOCOL = 13,
        /// argument buffer overflow
        OVERFLOW = 14,
        _,
    },
    .solaris, .illumos => enum(c_int) {
        /// address family for hostname not supported
        ADDRFAMILY = 1,
        /// name could not be resolved at this time
        AGAIN = 2,
        /// flags parameter had an invalid value
        BADFLAGS = 3,
        /// non-recoverable failure in name resolution
        FAIL = 4,
        /// address family not recognized
        FAMILY = 5,
        /// memory allocation failure
        MEMORY = 6,
        /// no address associated with hostname
        NODATA = 7,
        /// name does not resolve
        NONAME = 8,
        /// service not recognized for socket type
        SERVICE = 9,
        /// intended socket type was not recognized
        SOCKTYPE = 10,
        /// system error returned in errno
        SYSTEM = 11,
        /// argument buffer overflow
        OVERFLOW = 12,
        /// resolved protocol is unknown
        PROTOCOL = 13,

        _,
    },
    .openbsd => enum(c_int) {
        /// address family for hostname not supported
        ADDRFAMILY = -9,
        /// name could not be resolved at this time
        AGAIN = -3,
        /// flags parameter had an invalid value
        BADFLAGS = -1,
        /// non-recoverable failure in name resolution
        FAIL = -4,
        /// address family not recognized
        FAMILY = -6,
        /// memory allocation failure
        MEMORY = -10,
        /// no address associated with hostname
        NODATA = -5,
        /// name does not resolve
        NONAME = -2,
        /// service not recognized for socket type
        SERVICE = -8,
        /// intended socket type was not recognized
        SOCKTYPE = -7,
        /// system error returned in errno
        SYSTEM = -11,
        /// invalid value for hints
        BADHINTS = -12,
        /// resolved protocol is unknown
        PROTOCOL = -13,
        /// argument buffer overflow
        OVERFLOW = -14,
        _,
    },
    else => void,
};

pub const dl_iterate_phdr_callback = *const fn (info: *dl_phdr_info, size: usize, data: ?*anyopaque) callconv(.C) c_int;

pub const Stat = switch (native_os) {
    .linux => switch (native_arch) {
        .sparc64 => extern struct {
            dev: u64,
            __pad1: u16,
            ino: ino_t,
            mode: u32,
            nlink: u32,

            uid: u32,
            gid: u32,
            rdev: u64,
            __pad2: u16,

            size: off_t,
            blksize: isize,
            blocks: i64,

            atim: timespec,
            mtim: timespec,
            ctim: timespec,
            __reserved: [2]usize,

            pub fn atime(self: @This()) timespec {
                return self.atim;
            }

            pub fn mtime(self: @This()) timespec {
                return self.mtim;
            }

            pub fn ctime(self: @This()) timespec {
                return self.ctim;
            }
        },
        .mips, .mipsel => if (builtin.target.isMusl()) extern struct {
            dev: dev_t,
            __pad0: [2]i32,
            ino: ino_t,
            mode: mode_t,
            nlink: nlink_t,
            uid: uid_t,
            gid: gid_t,
            rdev: dev_t,
            __pad1: [2]i32,
            size: off_t,
            atim: timespec,
            mtim: timespec,
            ctim: timespec,
            blksize: blksize_t,
            __pad3: i32,
            blocks: blkcnt_t,
            __pad4: [14]i32,

            pub fn atime(self: @This()) timespec {
                return self.atim;
            }

            pub fn mtime(self: @This()) timespec {
                return self.mtim;
            }

            pub fn ctime(self: @This()) timespec {
                return self.ctim;
            }
        } else extern struct {
            dev: u32,
            __pad0: [3]u32,
            ino: ino_t,
            mode: mode_t,
            nlink: nlink_t,
            uid: uid_t,
            gid: gid_t,
            rdev: u32,
            __pad1: [3]u32,
            size: off_t,
            atim: timespec,
            mtim: timespec,
            ctim: timespec,
            blksize: blksize_t,
            __pad3: u32,
            blocks: blkcnt_t,
            __pad4: [14]u32,

            pub fn atime(self: @This()) timespec {
                return self.atim;
            }

            pub fn mtime(self: @This()) timespec {
                return self.mtim;
            }

            pub fn ctime(self: @This()) timespec {
                return self.ctim;
            }
        },
        .mips64, .mips64el => if (builtin.target.isMusl()) extern struct {
            dev: dev_t,
            __pad0: [3]i32,
            ino: ino_t,
            mode: mode_t,
            nlink: nlink_t,
            uid: uid_t,
            gid: gid_t,
            rdev: dev_t,
            __pad1: [2]u32,
            size: off_t,
            __pad2: i32,
            atim: timespec,
            mtim: timespec,
            ctim: timespec,
            blksize: blksize_t,
            __pad3: u32,
            blocks: blkcnt_t,
            __pad4: [14]i32,

            pub fn atime(self: @This()) timespec {
                return self.atim;
            }

            pub fn mtime(self: @This()) timespec {
                return self.mtim;
            }

            pub fn ctime(self: @This()) timespec {
                return self.ctim;
            }
        } else extern struct {
            dev: dev_t,
            __pad0: [3]u32,
            ino: ino_t,
            mode: mode_t,
            nlink: nlink_t,
            uid: uid_t,
            gid: gid_t,
            rdev: dev_t,
            __pad1: [3]u32,
            size: off_t,
            atim: timespec,
            mtim: timespec,
            ctim: timespec,
            blksize: blksize_t,
            __pad3: u32,
            blocks: blkcnt_t,
            __pad4: [14]i32,

            pub fn atime(self: @This()) timespec {
                return self.atim;
            }

            pub fn mtime(self: @This()) timespec {
                return self.mtim;
            }

            pub fn ctime(self: @This()) timespec {
                return self.ctim;
            }
        },

        else => std.os.linux.Stat, // libc stat is the same as kernel stat.
    },
    .emscripten => emscripten.Stat,
    .wasi => extern struct {
        dev: dev_t,
        ino: ino_t,
        nlink: nlink_t,
        mode: mode_t,
        uid: uid_t,
        gid: gid_t,
        __pad0: c_uint = 0,
        rdev: dev_t,
        size: off_t,
        blksize: blksize_t,
        blocks: blkcnt_t,
        atim: timespec,
        mtim: timespec,
        ctim: timespec,
        __reserved: [3]c_longlong = [3]c_longlong{ 0, 0, 0 },

        pub fn atime(self: @This()) timespec {
            return self.atim;
        }

        pub fn mtime(self: @This()) timespec {
            return self.mtim;
        }

        pub fn ctime(self: @This()) timespec {
            return self.ctim;
        }

        pub fn fromFilestat(st: wasi.filestat_t) Stat {
            return .{
                .dev = st.dev,
                .ino = st.ino,
                .mode = switch (st.filetype) {
                    .UNKNOWN => 0,
                    .BLOCK_DEVICE => S.IFBLK,
                    .CHARACTER_DEVICE => S.IFCHR,
                    .DIRECTORY => S.IFDIR,
                    .REGULAR_FILE => S.IFREG,
                    .SOCKET_DGRAM => S.IFSOCK,
                    .SOCKET_STREAM => S.IFIFO,
                    .SYMBOLIC_LINK => S.IFLNK,
                    _ => 0,
                },
                .nlink = st.nlink,
                .size = @intCast(st.size),
                .atim = timespec.fromTimestamp(st.atim),
                .mtim = timespec.fromTimestamp(st.mtim),
                .ctim = timespec.fromTimestamp(st.ctim),

                .uid = 0,
                .gid = 0,
                .rdev = 0,
                .blksize = 0,
                .blocks = 0,
            };
        }
    },
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        dev: i32,
        mode: u16,
        nlink: u16,
        ino: ino_t,
        uid: uid_t,
        gid: gid_t,
        rdev: i32,
        atimespec: timespec,
        mtimespec: timespec,
        ctimespec: timespec,
        birthtimespec: timespec,
        size: off_t,
        blocks: i64,
        blksize: i32,
        flags: u32,
        gen: u32,
        lspare: i32,
        qspare: [2]i64,

        pub fn atime(self: @This()) timespec {
            return self.atimespec;
        }

        pub fn mtime(self: @This()) timespec {
            return self.mtimespec;
        }

        pub fn ctime(self: @This()) timespec {
            return self.ctimespec;
        }

        pub fn birthtime(self: @This()) timespec {
            return self.birthtimespec;
        }
    },
    .freebsd => freebsd.Stat,
    .solaris, .illumos => extern struct {
        dev: dev_t,
        ino: ino_t,
        mode: mode_t,
        nlink: nlink_t,
        uid: uid_t,
        gid: gid_t,
        rdev: dev_t,
        size: off_t,
        atim: timespec,
        mtim: timespec,
        ctim: timespec,
        blksize: blksize_t,
        blocks: blkcnt_t,
        fstype: [16]u8,

        pub fn atime(self: @This()) timespec {
            return self.atim;
        }

        pub fn mtime(self: @This()) timespec {
            return self.mtim;
        }

        pub fn ctime(self: @This()) timespec {
            return self.ctim;
        }
    },
    .netbsd => extern struct {
        dev: dev_t,
        mode: mode_t,
        ino: ino_t,
        nlink: nlink_t,
        uid: uid_t,
        gid: gid_t,
        rdev: dev_t,
        atim: timespec,
        mtim: timespec,
        ctim: timespec,
        birthtim: timespec,
        size: off_t,
        blocks: blkcnt_t,
        blksize: blksize_t,
        flags: u32,
        gen: u32,
        __spare: [2]u32,

        pub fn atime(self: @This()) timespec {
            return self.atim;
        }

        pub fn mtime(self: @This()) timespec {
            return self.mtim;
        }

        pub fn ctime(self: @This()) timespec {
            return self.ctim;
        }

        pub fn birthtime(self: @This()) timespec {
            return self.birthtim;
        }
    },
    .dragonfly => extern struct {
        ino: ino_t,
        nlink: c_uint,
        dev: c_uint,
        mode: c_ushort,
        padding1: u16,
        uid: uid_t,
        gid: gid_t,
        rdev: c_uint,
        atim: timespec,
        mtim: timespec,
        ctim: timespec,
        size: c_ulong,
        blocks: i64,
        blksize: u32,
        flags: u32,
        gen: u32,
        lspare: i32,
        qspare1: i64,
        qspare2: i64,
        pub fn atime(self: @This()) timespec {
            return self.atim;
        }

        pub fn mtime(self: @This()) timespec {
            return self.mtim;
        }

        pub fn ctime(self: @This()) timespec {
            return self.ctim;
        }
    },
    .haiku => extern struct {
        dev: dev_t,
        ino: ino_t,
        mode: mode_t,
        nlink: nlink_t,
        uid: uid_t,
        gid: gid_t,
        size: off_t,
        rdev: dev_t,
        blksize: blksize_t,
        atim: timespec,
        mtim: timespec,
        ctim: timespec,
        crtim: timespec,
        type: u32,
        blocks: blkcnt_t,

        pub fn atime(self: @This()) timespec {
            return self.atim;
        }
        pub fn mtime(self: @This()) timespec {
            return self.mtim;
        }
        pub fn ctime(self: @This()) timespec {
            return self.ctim;
        }
        pub fn birthtime(self: @This()) timespec {
            return self.crtim;
        }
    },
    .openbsd => extern struct {
        mode: mode_t,
        dev: dev_t,
        ino: ino_t,
        nlink: nlink_t,
        uid: uid_t,
        gid: gid_t,
        rdev: dev_t,
        atim: timespec,
        mtim: timespec,
        ctim: timespec,
        size: off_t,
        blocks: blkcnt_t,
        blksize: blksize_t,
        flags: u32,
        gen: u32,
        birthtim: timespec,

        pub fn atime(self: @This()) timespec {
            return self.atim;
        }

        pub fn mtime(self: @This()) timespec {
            return self.mtim;
        }

        pub fn ctime(self: @This()) timespec {
            return self.ctim;
        }

        pub fn birthtime(self: @This()) timespec {
            return self.birthtim;
        }
    },
    else => void,
};

pub const pthread_mutex_t = switch (native_os) {
    .linux => extern struct {
        data: [data_len]u8 align(@alignOf(usize)) = [_]u8{0} ** data_len,

        const data_len = switch (native_abi) {
            .musl, .musleabi, .musleabihf => if (@sizeOf(usize) == 8) 40 else 24,
            .gnu, .gnuabin32, .gnuabi64, .gnueabi, .gnueabihf, .gnux32 => switch (native_arch) {
                .aarch64 => 48,
                .x86_64 => if (native_abi == .gnux32) 32 else 40,
                .mips64, .powerpc64, .powerpc64le, .sparc64 => 40,
                else => if (@sizeOf(usize) == 8) 40 else 24,
            },
            .android, .androideabi => if (@sizeOf(usize) == 8) 40 else 4,
            else => @compileError("unsupported ABI"),
        };
    },
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        sig: c_long = 0x32AAABA7,
        data: [data_len]u8 = [_]u8{0} ** data_len,

        const data_len = if (@sizeOf(usize) == 8) 56 else 40;
    },
    .freebsd, .dragonfly, .openbsd => extern struct {
        inner: ?*anyopaque = null,
    },
    .hermit => extern struct {
        ptr: usize = maxInt(usize),
    },
    .netbsd => extern struct {
        magic: u32 = 0x33330003,
        errorcheck: padded_pthread_spin_t = 0,
        ceiling: padded_pthread_spin_t = 0,
        owner: usize = 0,
        waiters: ?*u8 = null,
        recursed: u32 = 0,
        spare2: ?*anyopaque = null,
    },
    .haiku => extern struct {
        flags: u32 = 0,
        lock: i32 = 0,
        unused: i32 = -42,
        owner: i32 = -1,
        owner_count: i32 = 0,
    },
    .solaris, .illumos => extern struct {
        flag1: u16 = 0,
        flag2: u8 = 0,
        ceiling: u8 = 0,
        type: u16 = 0,
        magic: u16 = 0x4d58,
        lock: u64 = 0,
        data: u64 = 0,
    },
    .fuchsia => extern struct {
        data: [40]u8 align(@alignOf(usize)) = [_]u8{0} ** 40,
    },
    .emscripten => extern struct {
        data: [24]u8 align(4) = [_]u8{0} ** 24,
    },
    else => void,
};

pub const pthread_cond_t = switch (native_os) {
    .linux => extern struct {
        data: [48]u8 align(@alignOf(usize)) = [_]u8{0} ** 48,
    },
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        sig: c_long = 0x3CB0B1BB,
        data: [data_len]u8 = [_]u8{0} ** data_len,
        const data_len = if (@sizeOf(usize) == 8) 40 else 24;
    },
    .freebsd, .dragonfly, .openbsd => extern struct {
        inner: ?*anyopaque = null,
    },
    .hermit => extern struct {
        ptr: usize = maxInt(usize),
    },
    .netbsd => extern struct {
        magic: u32 = 0x55550005,
        lock: pthread_spin_t = 0,
        waiters_first: ?*u8 = null,
        waiters_last: ?*u8 = null,
        mutex: ?*pthread_mutex_t = null,
        private: ?*anyopaque = null,
    },
    .haiku => extern struct {
        flags: u32 = 0,
        unused: i32 = -42,
        mutex: ?*anyopaque = null,
        waiter_count: i32 = 0,
        lock: i32 = 0,
    },
    .solaris, .illumos => extern struct {
        flag: [4]u8 = [_]u8{0} ** 4,
        type: u16 = 0,
        magic: u16 = 0x4356,
        data: u64 = 0,
    },
    .fuchsia, .emscripten => extern struct {
        data: [48]u8 align(@alignOf(usize)) = [_]u8{0} ** 48,
    },
    else => void,
};

pub const pthread_rwlock_t = switch (native_os) {
    .linux => switch (native_abi) {
        .android, .androideabi => switch (@sizeOf(usize)) {
            4 => extern struct {
                data: [40]u8 align(@alignOf(usize)) = [_]u8{0} ** 40,
            },
            8 => extern struct {
                data: [56]u8 align(@alignOf(usize)) = [_]u8{0} ** 56,
            },
            else => @compileError("impossible pointer size"),
        },
        else => extern struct {
            data: [56]u8 align(@alignOf(usize)) = [_]u8{0} ** 56,
        },
    },
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        sig: c_long = 0x2DA8B3B4,
        data: [192]u8 = [_]u8{0} ** 192,
    },
    .freebsd, .dragonfly, .openbsd => extern struct {
        ptr: ?*anyopaque = null,
    },
    .hermit => extern struct {
        ptr: usize = maxInt(usize),
    },
    .netbsd => extern struct {
        magic: c_uint = 0x99990009,
        interlock: switch (builtin.cpu.arch) {
            .aarch64, .sparc, .x86_64, .x86 => u8,
            .arm, .powerpc => c_int,
            else => unreachable,
        } = 0,
        rblocked_first: ?*u8 = null,
        rblocked_last: ?*u8 = null,
        wblocked_first: ?*u8 = null,
        wblocked_last: ?*u8 = null,
        nreaders: c_uint = 0,
        owner: ?pthread_t = null,
        private: ?*anyopaque = null,
    },
    .solaris, .illumos => extern struct {
        readers: i32 = 0,
        type: u16 = 0,
        magic: u16 = 0x5257,
        mutex: pthread_mutex_t = .{},
        readercv: pthread_cond_t = .{},
        writercv: pthread_cond_t = .{},
    },
    .fuchsia => extern struct {
        size: [56]u8 align(@alignOf(usize)) = [_]u8{0} ** 56,
    },
    .emscripten => extern struct {
        size: [32]u8 align(4) = [_]u8{0} ** 32,
    },
    else => void,
};

pub const pthread_attr_t = switch (native_os) {
    .linux, .emscripten, .dragonfly => extern struct {
        __size: [56]u8,
        __align: c_long,
    },
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        __sig: c_long,
        __opaque: [56]u8,
    },
    .freebsd => extern struct {
        inner: ?*anyopaque = null,
    },
    .solaris, .illumos => extern struct {
        mutexattr: ?*anyopaque = null,
    },
    .netbsd => extern struct {
        magic: u32,
        flags: i32,
        private: ?*anyopaque,
    },
    .haiku => extern struct {
        detach_state: i32,
        sched_priority: i32,
        stack_size: i32,
        guard_size: i32,
        stack_address: ?*anyopaque,
    },
    .openbsd => extern struct {
        inner: ?*anyopaque = null,
    },
    else => void,
};

pub const pthread_key_t = switch (native_os) {
    .linux, .emscripten => c_uint,
    .openbsd, .solaris, .illumos => c_int,
    else => void,
};

pub const padded_pthread_spin_t = switch (native_os) {
    .netbsd => switch (builtin.cpu.arch) {
        .x86, .x86_64 => u32,
        .sparc, .sparc64 => u32,
        else => pthread_spin_t,
    },
    else => void,
};

pub const pthread_spin_t = switch (native_os) {
    .netbsd => switch (builtin.cpu.arch) {
        .aarch64, .aarch64_be => u8,
        .mips, .mipsel, .mips64, .mips64el => u32,
        .powerpc, .powerpc64, .powerpc64le => i32,
        .x86, .x86_64 => u8,
        .arm, .armeb, .thumb, .thumbeb => i32,
        .sparc, .sparc64 => u8,
        .riscv32, .riscv64 => u32,
        else => @compileError("undefined pthread_spin_t for this arch"),
    },
    else => void,
};

pub const sem_t = switch (native_os) {
    .linux, .emscripten => extern struct {
        __size: [4 * @sizeOf(usize)]u8 align(@alignOf(usize)),
    },
    .macos, .ios, .tvos, .watchos, .visionos => c_int,
    .freebsd => extern struct {
        _magic: u32,
        _kern: extern struct {
            _count: u32,
            _flags: u32,
        },
        _padding: u32,
    },
    .solaris, .illumos => extern struct {
        count: u32 = 0,
        type: u16 = 0,
        magic: u16 = 0x534d,
        __pad1: [3]u64 = [_]u64{0} ** 3,
        __pad2: [2]u64 = [_]u64{0} ** 2,
    },
    .openbsd, .netbsd, .dragonfly => ?*opaque {},
    .haiku => extern struct {
        type: i32,
        u: extern union {
            named_sem_id: i32,
            unnamed_sem: i32,
        },
        padding: [2]i32,
    },
    else => void,
};

/// Renamed from `kevent` to `Kevent` to avoid conflict with function name.
pub const Kevent = switch (native_os) {
    .netbsd => extern struct {
        ident: usize,
        filter: i32,
        flags: u32,
        fflags: u32,
        data: i64,
        udata: usize,
    },
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        ident: usize,
        filter: i16,
        flags: u16,
        fflags: u32,
        data: isize,
        udata: usize,

        // sys/types.h on macos uses #pragma pack(4) so these checks are
        // to make sure the struct is laid out the same. These values were
        // produced from C code using the offsetof macro.
        comptime {
            assert(@offsetOf(@This(), "ident") == 0);
            assert(@offsetOf(@This(), "filter") == 8);
            assert(@offsetOf(@This(), "flags") == 10);
            assert(@offsetOf(@This(), "fflags") == 12);
            assert(@offsetOf(@This(), "data") == 16);
            assert(@offsetOf(@This(), "udata") == 24);
        }
    },
    .freebsd => extern struct {
        /// Identifier for this event.
        ident: usize,
        /// Filter for event.
        filter: i16,
        /// Action flags for kqueue.
        flags: u16,
        /// Filter flag value.
        fflags: u32,
        /// Filter data value.
        data: i64,
        /// Opaque user data identifier.
        udata: usize,
        /// Future extensions.
        _ext: [4]u64 = [_]u64{0} ** 4,
    },
    .dragonfly => extern struct {
        ident: usize,
        filter: c_short,
        flags: c_ushort,
        fflags: c_uint,
        data: isize,
        udata: usize,
    },
    .openbsd => extern struct {
        ident: usize,
        filter: c_short,
        flags: u16,
        fflags: c_uint,
        data: i64,
        udata: usize,
    },
    else => void,
};

pub const port_t = switch (native_os) {
    .solaris, .illumos => c_int,
    else => void,
};

pub const port_event = switch (native_os) {
    .solaris, .illumos => extern struct {
        events: u32,
        /// Event source.
        source: u16,
        __pad: u16,
        /// Source-specific object.
        object: ?*anyopaque,
        /// User cookie.
        cookie: ?*anyopaque,
    },
    else => void,
};

pub const AT = switch (native_os) {
    .linux => linux.AT,
    .windows => struct {
        /// Remove directory instead of unlinking file
        pub const REMOVEDIR = 0x200;
    },
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const FDCWD = -2;
        /// Use effective ids in access check
        pub const EACCESS = 0x0010;
        /// Act on the symlink itself not the target
        pub const SYMLINK_NOFOLLOW = 0x0020;
        /// Act on target of symlink
        pub const SYMLINK_FOLLOW = 0x0040;
        /// Path refers to directory
        pub const REMOVEDIR = 0x0080;
    },
    .freebsd => struct {
        /// Magic value that specify the use of the current working directory
        /// to determine the target of relative file paths in the openat() and
        /// similar syscalls.
        pub const FDCWD = -100;
        /// Check access using effective user and group ID
        pub const EACCESS = 0x0100;
        /// Do not follow symbolic links
        pub const SYMLINK_NOFOLLOW = 0x0200;
        /// Follow symbolic link
        pub const SYMLINK_FOLLOW = 0x0400;
        /// Remove directory instead of file
        pub const REMOVEDIR = 0x0800;
        /// Fail if not under dirfd
        pub const BENEATH = 0x1000;
    },
    .netbsd => struct {
        /// Magic value that specify the use of the current working directory
        /// to determine the target of relative file paths in the openat() and
        /// similar syscalls.
        pub const FDCWD = -100;
        /// Check access using effective user and group ID
        pub const EACCESS = 0x0100;
        /// Do not follow symbolic links
        pub const SYMLINK_NOFOLLOW = 0x0200;
        /// Follow symbolic link
        pub const SYMLINK_FOLLOW = 0x0400;
        /// Remove directory instead of file
        pub const REMOVEDIR = 0x0800;
    },
    .dragonfly => struct {
        pub const FDCWD = -328243;
        pub const SYMLINK_NOFOLLOW = 1;
        pub const REMOVEDIR = 2;
        pub const EACCESS = 4;
        pub const SYMLINK_FOLLOW = 8;
    },
    .openbsd => struct {
        /// Magic value that specify the use of the current working directory
        /// to determine the target of relative file paths in the openat() and
        /// similar syscalls.
        pub const FDCWD = -100;
        /// Check access using effective user and group ID
        pub const EACCESS = 0x01;
        /// Do not follow symbolic links
        pub const SYMLINK_NOFOLLOW = 0x02;
        /// Follow symbolic link
        pub const SYMLINK_FOLLOW = 0x04;
        /// Remove directory instead of file
        pub const REMOVEDIR = 0x08;
    },
    .haiku => struct {
        pub const FDCWD = -1;
        pub const SYMLINK_NOFOLLOW = 0x01;
        pub const SYMLINK_FOLLOW = 0x02;
        pub const REMOVEDIR = 0x04;
        pub const EACCESS = 0x08;
    },
    .solaris, .illumos => struct {
        /// Magic value that specify the use of the current working directory
        /// to determine the target of relative file paths in the openat() and
        /// similar syscalls.
        pub const FDCWD: fd_t = @bitCast(@as(u32, 0xffd19553));
        /// Do not follow symbolic links
        pub const SYMLINK_NOFOLLOW = 0x1000;
        /// Follow symbolic link
        pub const SYMLINK_FOLLOW = 0x2000;
        /// Remove directory instead of file
        pub const REMOVEDIR = 0x1;
        pub const TRIGGER = 0x2;
        /// Check access using effective user and group ID
        pub const EACCESS = 0x4;
    },
    .emscripten => struct {
        pub const FDCWD = -100;
        pub const SYMLINK_NOFOLLOW = 0x100;
        pub const REMOVEDIR = 0x200;
        pub const SYMLINK_FOLLOW = 0x400;
        pub const NO_AUTOMOUNT = 0x800;
        pub const EMPTY_PATH = 0x1000;
        pub const STATX_SYNC_TYPE = 0x6000;
        pub const STATX_SYNC_AS_STAT = 0x0000;
        pub const STATX_FORCE_SYNC = 0x2000;
        pub const STATX_DONT_SYNC = 0x4000;
        pub const RECURSIVE = 0x8000;
    },
    .wasi => struct {
        pub const SYMLINK_NOFOLLOW = 0x100;
        pub const SYMLINK_FOLLOW = 0x400;
        pub const REMOVEDIR: u32 = 0x4;
        /// When linking libc, we follow their convention and use -2 for current working directory.
        /// However, without libc, Zig does a different convention: it assumes the
        /// current working directory is the first preopen. This behavior can be
        /// overridden with a public function called `wasi_cwd` in the root source
        /// file.
        pub const FDCWD: fd_t = if (builtin.link_libc) -2 else 3;
    },

    else => void,
};

pub const O = switch (native_os) {
    .linux => linux.O,
    .emscripten => packed struct(u32) {
        ACCMODE: std.posix.ACCMODE = .RDONLY,
        _2: u4 = 0,
        CREAT: bool = false,
        EXCL: bool = false,
        NOCTTY: bool = false,
        TRUNC: bool = false,
        APPEND: bool = false,
        NONBLOCK: bool = false,
        DSYNC: bool = false,
        ASYNC: bool = false,
        DIRECT: bool = false,
        LARGEFILE: bool = false,
        DIRECTORY: bool = false,
        NOFOLLOW: bool = false,
        NOATIME: bool = false,
        CLOEXEC: bool = false,
        SYNC: bool = false,
        PATH: bool = false,
        TMPFILE: bool = false,
        _: u9 = 0,
    },
    .wasi => packed struct(u32) {
        APPEND: bool = false,
        DSYNC: bool = false,
        NONBLOCK: bool = false,
        RSYNC: bool = false,
        SYNC: bool = false,
        _5: u7 = 0,
        CREAT: bool = false,
        DIRECTORY: bool = false,
        EXCL: bool = false,
        TRUNC: bool = false,
        _16: u8 = 0,
        NOFOLLOW: bool = false,
        EXEC: bool = false,
        read: bool = false,
        SEARCH: bool = false,
        write: bool = false,
        _: u3 = 0,
    },
    .solaris, .illumos => packed struct(u32) {
        ACCMODE: std.posix.ACCMODE = .RDONLY,
        NDELAY: bool = false,
        APPEND: bool = false,
        SYNC: bool = false,
        _5: u1 = 0,
        DSYNC: bool = false,
        NONBLOCK: bool = false,
        CREAT: bool = false,
        TRUNC: bool = false,
        EXCL: bool = false,
        NOCTTY: bool = false,
        _12: u1 = 0,
        LARGEFILE: bool = false,
        XATTR: bool = false,
        RSYNC: bool = false,
        _16: u1 = 0,
        NOFOLLOW: bool = false,
        NOLINKS: bool = false,
        _19: u2 = 0,
        SEARCH: bool = false,
        EXEC: bool = false,
        CLOEXEC: bool = false,
        DIRECTORY: bool = false,
        DIRECT: bool = false,
        _: u6 = 0,
    },
    .netbsd => packed struct(u32) {
        ACCMODE: std.posix.ACCMODE = .RDONLY,
        NONBLOCK: bool = false,
        APPEND: bool = false,
        SHLOCK: bool = false,
        EXLOCK: bool = false,
        ASYNC: bool = false,
        SYNC: bool = false,
        NOFOLLOW: bool = false,
        CREAT: bool = false,
        TRUNC: bool = false,
        EXCL: bool = false,
        _12: u3 = 0,
        NOCTTY: bool = false,
        DSYNC: bool = false,
        RSYNC: bool = false,
        ALT_IO: bool = false,
        DIRECT: bool = false,
        _20: u1 = 0,
        DIRECTORY: bool = false,
        CLOEXEC: bool = false,
        SEARCH: bool = false,
        _: u8 = 0,
    },
    .openbsd => packed struct(u32) {
        ACCMODE: std.posix.ACCMODE = .RDONLY,
        NONBLOCK: bool = false,
        APPEND: bool = false,
        SHLOCK: bool = false,
        EXLOCK: bool = false,
        ASYNC: bool = false,
        SYNC: bool = false,
        NOFOLLOW: bool = false,
        CREAT: bool = false,
        TRUNC: bool = false,
        EXCL: bool = false,
        _12: u3 = 0,
        NOCTTY: bool = false,
        CLOEXEC: bool = false,
        DIRECTORY: bool = false,
        _: u14 = 0,
    },
    .haiku => packed struct(u32) {
        ACCMODE: std.posix.ACCMODE = .RDONLY,
        _2: u4 = 0,
        CLOEXEC: bool = false,
        NONBLOCK: bool = false,
        EXCL: bool = false,
        CREAT: bool = false,
        TRUNC: bool = false,
        APPEND: bool = false,
        NOCTTY: bool = false,
        NOTRAVERSE: bool = false,
        _14: u2 = 0,
        SYNC: bool = false,
        RSYNC: bool = false,
        DSYNC: bool = false,
        NOFOLLOW: bool = false,
        DIRECT: bool = false,
        DIRECTORY: bool = false,
        _: u10 = 0,
    },
    .macos, .ios, .tvos, .watchos, .visionos => packed struct(u32) {
        ACCMODE: std.posix.ACCMODE = .RDONLY,
        NONBLOCK: bool = false,
        APPEND: bool = false,
        SHLOCK: bool = false,
        EXLOCK: bool = false,
        ASYNC: bool = false,
        SYNC: bool = false,
        NOFOLLOW: bool = false,
        CREAT: bool = false,
        TRUNC: bool = false,
        EXCL: bool = false,
        _12: u3 = 0,
        EVTONLY: bool = false,
        _16: u1 = 0,
        NOCTTY: bool = false,
        _18: u2 = 0,
        DIRECTORY: bool = false,
        SYMLINK: bool = false,
        DSYNC: bool = false,
        _23: u1 = 0,
        CLOEXEC: bool = false,
        _25: u4 = 0,
        ALERT: bool = false,
        _30: u1 = 0,
        POPUP: bool = false,
    },
    .dragonfly => packed struct(u32) {
        ACCMODE: std.posix.ACCMODE = .RDONLY,
        NONBLOCK: bool = false,
        APPEND: bool = false,
        SHLOCK: bool = false,
        EXLOCK: bool = false,
        ASYNC: bool = false,
        SYNC: bool = false,
        NOFOLLOW: bool = false,
        CREAT: bool = false,
        TRUNC: bool = false,
        EXCL: bool = false,
        _12: u3 = 0,
        NOCTTY: bool = false,
        DIRECT: bool = false,
        CLOEXEC: bool = false,
        FBLOCKING: bool = false,
        FNONBLOCKING: bool = false,
        FAPPEND: bool = false,
        FOFFSET: bool = false,
        FSYNCWRITE: bool = false,
        FASYNCWRITE: bool = false,
        _24: u3 = 0,
        DIRECTORY: bool = false,
        _: u4 = 0,
    },
    .freebsd => packed struct(u32) {
        ACCMODE: std.posix.ACCMODE = .RDONLY,
        NONBLOCK: bool = false,
        APPEND: bool = false,
        SHLOCK: bool = false,
        EXLOCK: bool = false,
        ASYNC: bool = false,
        SYNC: bool = false,
        NOFOLLOW: bool = false,
        CREAT: bool = false,
        TRUNC: bool = false,
        EXCL: bool = false,
        DSYNC: bool = false,
        _13: u2 = 0,
        NOCTTY: bool = false,
        DIRECT: bool = false,
        DIRECTORY: bool = false,
        NOATIME: bool = false,
        _19: u1 = 0,
        CLOEXEC: bool = false,
        PATH: bool = false,
        TMPFILE: bool = false,
        _: u9 = 0,
    },
    else => void,
};

pub const MAP = switch (native_os) {
    .linux => linux.MAP,
    .emscripten => packed struct(u32) {
        TYPE: enum(u4) {
            SHARED = 0x01,
            PRIVATE = 0x02,
            SHARED_VALIDATE = 0x03,
        },
        FIXED: bool = false,
        ANONYMOUS: bool = false,
        _6: u2 = 0,
        GROWSDOWN: bool = false,
        _9: u2 = 0,
        DENYWRITE: bool = false,
        EXECUTABLE: bool = false,
        LOCKED: bool = false,
        NORESERVE: bool = false,
        POPULATE: bool = false,
        NONBLOCK: bool = false,
        STACK: bool = false,
        HUGETLB: bool = false,
        SYNC: bool = false,
        FIXED_NOREPLACE: bool = false,
        _: u11 = 0,
    },
    .solaris, .illumos => packed struct(u32) {
        TYPE: enum(u4) {
            SHARED = 0x01,
            PRIVATE = 0x02,
        },
        FIXED: bool = false,
        RENAME: bool = false,
        NORESERVE: bool = false,
        @"32BIT": bool = false,
        ANONYMOUS: bool = false,
        ALIGN: bool = false,
        TEXT: bool = false,
        INITDATA: bool = false,
        _: u20 = 0,
    },
    .netbsd => packed struct(u32) {
        TYPE: enum(u2) {
            SHARED = 0x01,
            PRIVATE = 0x02,
        },
        REMAPDUP: bool = false,
        _3: u1 = 0,
        FIXED: bool = false,
        RENAME: bool = false,
        NORESERVE: bool = false,
        INHERIT: bool = false,
        _8: u1 = 0,
        HASSEMAPHORE: bool = false,
        TRYFIXED: bool = false,
        WIRED: bool = false,
        ANONYMOUS: bool = false,
        STACK: bool = false,
        _: u18 = 0,
    },
    .openbsd => packed struct(u32) {
        TYPE: enum(u4) {
            SHARED = 0x01,
            PRIVATE = 0x02,
        },
        FIXED: bool = false,
        _5: u7 = 0,
        ANONYMOUS: bool = false,
        _13: u1 = 0,
        STACK: bool = false,
        CONCEAL: bool = false,
        _: u16 = 0,
    },
    .haiku => packed struct(u32) {
        TYPE: enum(u2) {
            SHARED = 0x01,
            PRIVATE = 0x02,
        },
        FIXED: bool = false,
        ANONYMOUS: bool = false,
        NORESERVE: bool = false,
        _: u27 = 0,
    },
    .macos, .ios, .tvos, .watchos, .visionos => packed struct(u32) {
        TYPE: enum(u4) {
            SHARED = 0x01,
            PRIVATE = 0x02,
        },
        FIXED: bool = false,
        _5: u1 = 0,
        NORESERVE: bool = false,
        _7: u2 = 0,
        HASSEMAPHORE: bool = false,
        NOCACHE: bool = false,
        _11: u1 = 0,
        ANONYMOUS: bool = false,
        _: u19 = 0,
    },
    .dragonfly => packed struct(u32) {
        TYPE: enum(u4) {
            SHARED = 0x01,
            PRIVATE = 0x02,
        },
        FIXED: bool = false,
        RENAME: bool = false,
        NORESERVE: bool = false,
        INHERIT: bool = false,
        NOEXTEND: bool = false,
        HASSEMAPHORE: bool = false,
        STACK: bool = false,
        NOSYNC: bool = false,
        ANONYMOUS: bool = false,
        VPAGETABLE: bool = false,
        _14: u2 = 0,
        TRYFIXED: bool = false,
        NOCORE: bool = false,
        SIZEALIGN: bool = false,
        _: u13 = 0,
    },
    .freebsd => packed struct(u32) {
        TYPE: enum(u4) {
            SHARED = 0x01,
            PRIVATE = 0x02,
        },
        FIXED: bool = false,
        _5: u5 = 0,
        STACK: bool = false,
        NOSYNC: bool = false,
        ANONYMOUS: bool = false,
        GUARD: bool = false,
        EXCL: bool = false,
        _15: u2 = 0,
        NOCORE: bool = false,
        PREFAULT_READ: bool = false,
        @"32BIT": bool = false,
        _: u12 = 0,
    },
    else => void,
};

/// Used by libc to communicate failure. Not actually part of the underlying syscall.
pub const MAP_FAILED: *anyopaque = @ptrFromInt(maxInt(usize));

pub const cc_t = u8;

/// Indices into the `cc` array in the `termios` struct.
pub const V = switch (native_os) {
    .linux => linux.V,
    .macos, .ios, .tvos, .watchos, .visionos, .netbsd, .openbsd => enum {
        EOF,
        EOL,
        EOL2,
        ERASE,
        WERASE,
        KILL,
        REPRINT,
        reserved,
        INTR,
        QUIT,
        SUSP,
        DSUSP,
        START,
        STOP,
        LNEXT,
        DISCARD,
        MIN,
        TIME,
        STATUS,
    },
    .freebsd => enum {
        EOF,
        EOL,
        EOL2,
        ERASE,
        WERASE,
        KILL,
        REPRINT,
        ERASE2,
        INTR,
        QUIT,
        SUSP,
        DSUSP,
        START,
        STOP,
        LNEXT,
        DISCARD,
        MIN,
        TIME,
        STATUS,
    },
    .haiku => enum {
        INTR,
        QUIT,
        ERASE,
        KILL,
        EOF,
        EOL,
        EOL2,
        SWTCH,
        START,
        STOP,
        SUSP,
    },
    .solaris, .illumos => enum {
        INTR,
        QUIT,
        ERASE,
        KILL,
        EOF,
        EOL,
        EOL2,
        SWTCH,
        START,
        STOP,
        SUSP,
        DSUSP,
        REPRINT,
        DISCARD,
        WERASE,
        LNEXT,
        STATUS,
        ERASE2,
    },
    .emscripten, .wasi => enum {
        INTR,
        QUIT,
        ERASE,
        KILL,
        EOF,
        TIME,
        MIN,
        SWTC,
        START,
        STOP,
        SUSP,
        EOL,
        REPRINT,
        DISCARD,
        WERASE,
        LNEXT,
        EOL2,
    },
    else => void,
};

pub const NCCS = switch (native_os) {
    .linux => linux.NCCS,
    .macos, .ios, .tvos, .watchos, .visionos, .freebsd, .netbsd, .openbsd, .dragonfly => 20,
    .haiku => 11,
    .solaris, .illumos => 19,
    .emscripten, .wasi => 32,
    else => void,
};

pub const termios = switch (native_os) {
    .linux => linux.termios,
    .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        iflag: tc_iflag_t,
        oflag: tc_oflag_t,
        cflag: tc_cflag_t,
        lflag: tc_lflag_t,
        cc: [NCCS]cc_t,
        ispeed: speed_t align(8),
        ospeed: speed_t,
    },
    .freebsd, .netbsd, .dragonfly, .openbsd => extern struct {
        iflag: tc_iflag_t,
        oflag: tc_oflag_t,
        cflag: tc_cflag_t,
        lflag: tc_lflag_t,
        cc: [NCCS]cc_t,
        ispeed: speed_t,
        ospeed: speed_t,
    },
    .haiku => extern struct {
        iflag: tc_iflag_t,
        oflag: tc_oflag_t,
        cflag: tc_cflag_t,
        lflag: tc_lflag_t,
        line: cc_t,
        ispeed: speed_t,
        ospeed: speed_t,
        cc: [NCCS]cc_t,
    },
    .solaris, .illumos => extern struct {
        iflag: tc_iflag_t,
        oflag: tc_oflag_t,
        cflag: tc_cflag_t,
        lflag: tc_lflag_t,
        cc: [NCCS]cc_t,
    },
    .emscripten, .wasi => extern struct {
        iflag: tc_iflag_t,
        oflag: tc_oflag_t,
        cflag: tc_cflag_t,
        lflag: tc_lflag_t,
        line: cc_t,
        cc: [NCCS]cc_t,
        ispeed: speed_t,
        ospeed: speed_t,
    },
    else => void,
};

pub const tc_iflag_t = switch (native_os) {
    .linux => linux.tc_iflag_t,
    .macos, .ios, .tvos, .watchos, .visionos => packed struct(u64) {
        IGNBRK: bool = false,
        BRKINT: bool = false,
        IGNPAR: bool = false,
        PARMRK: bool = false,
        INPCK: bool = false,
        ISTRIP: bool = false,
        INLCR: bool = false,
        IGNCR: bool = false,
        ICRNL: bool = false,
        IXON: bool = false,
        IXOFF: bool = false,
        IXANY: bool = false,
        _12: u1 = 0,
        IMAXBEL: bool = false,
        IUTF8: bool = false,
        _: u49 = 0,
    },
    .netbsd, .freebsd, .dragonfly => packed struct(u32) {
        IGNBRK: bool = false,
        BRKINT: bool = false,
        IGNPAR: bool = false,
        PARMRK: bool = false,
        INPCK: bool = false,
        ISTRIP: bool = false,
        INLCR: bool = false,
        IGNCR: bool = false,
        ICRNL: bool = false,
        IXON: bool = false,
        IXOFF: bool = false,
        IXANY: bool = false,
        _12: u1 = 0,
        IMAXBEL: bool = false,
        _: u18 = 0,
    },
    .openbsd => packed struct(u32) {
        IGNBRK: bool = false,
        BRKINT: bool = false,
        IGNPAR: bool = false,
        PARMRK: bool = false,
        INPCK: bool = false,
        ISTRIP: bool = false,
        INLCR: bool = false,
        IGNCR: bool = false,
        ICRNL: bool = false,
        IXON: bool = false,
        IXOFF: bool = false,
        IXANY: bool = false,
        IUCLC: bool = false,
        IMAXBEL: bool = false,
        _: u18 = 0,
    },
    .haiku => packed struct(u32) {
        IGNBRK: bool = false,
        BRKINT: bool = false,
        IGNPAR: bool = false,
        PARMRK: bool = false,
        INPCK: bool = false,
        ISTRIP: bool = false,
        INLCR: bool = false,
        IGNCR: bool = false,
        ICRNL: bool = false,
        IUCLC: bool = false,
        IXON: bool = false,
        IXANY: bool = false,
        IXOFF: bool = false,
        _: u19 = 0,
    },
    .solaris, .illumos => packed struct(u32) {
        IGNBRK: bool = false,
        BRKINT: bool = false,
        IGNPAR: bool = false,
        PARMRK: bool = false,
        INPCK: bool = false,
        ISTRIP: bool = false,
        INLCR: bool = false,
        IGNCR: bool = false,
        ICRNL: bool = false,
        IUCLC: bool = false,
        IXON: bool = false,
        IXANY: bool = false,
        _12: u1 = 0,
        IMAXBEL: bool = false,
        _14: u1 = 0,
        DOSMODE: bool = false,
        _: u16 = 0,
    },
    .emscripten, .wasi => packed struct(u32) {
        IGNBRK: bool = false,
        BRKINT: bool = false,
        IGNPAR: bool = false,
        PARMRK: bool = false,
        INPCK: bool = false,
        ISTRIP: bool = false,
        INLCR: bool = false,
        IGNCR: bool = false,
        ICRNL: bool = false,
        IUCLC: bool = false,
        IXON: bool = false,
        IXANY: bool = false,
        IXOFF: bool = false,
        IMAXBEL: bool = false,
        IUTF8: bool = false,
        _: u17 = 0,
    },
    else => void,
};

pub const tc_oflag_t = switch (native_os) {
    .linux => linux.tc_oflag_t,
    .macos, .ios, .tvos, .watchos, .visionos => packed struct(u64) {
        OPOST: bool = false,
        ONLCR: bool = false,
        OXTABS: bool = false,
        ONOEOT: bool = false,
        OCRNL: bool = false,
        ONOCR: bool = false,
        ONLRET: bool = false,
        OFILL: bool = false,
        NLDLY: u2 = 0,
        TABDLY: u2 = 0,
        CRDLY: u2 = 0,
        FFDLY: u1 = 0,
        BSDLY: u1 = 0,
        VTDLY: u1 = 0,
        OFDEL: bool = false,
        _: u46 = 0,
    },
    .netbsd => packed struct(u32) {
        OPOST: bool = false,
        ONLCR: bool = false,
        OXTABS: bool = false,
        ONOEOT: bool = false,
        OCRNL: bool = false,
        _5: u1 = 0,
        ONOCR: bool = false,
        ONLRET: bool = false,
        _: u24 = 0,
    },
    .openbsd => packed struct(u32) {
        OPOST: bool = false,
        ONLCR: bool = false,
        OXTABS: bool = false,
        ONOEOT: bool = false,
        OCRNL: bool = false,
        OLCUC: bool = false,
        ONOCR: bool = false,
        ONLRET: bool = false,
        _: u24 = 0,
    },
    .freebsd, .dragonfly => packed struct(u32) {
        OPOST: bool = false,
        ONLCR: bool = false,
        _2: u1 = 0,
        ONOEOT: bool = false,
        OCRNL: bool = false,
        ONOCR: bool = false,
        ONLRET: bool = false,
        _: u25 = 0,
    },
    .solaris, .illumos => packed struct(u32) {
        OPOST: bool = false,
        OLCUC: bool = false,
        ONLCR: bool = false,
        OCRNL: bool = false,
        ONOCR: bool = false,
        ONLRET: bool = false,
        OFILL: bool = false,
        OFDEL: bool = false,
        NLDLY: u1 = 0,
        CRDLY: u2 = 0,
        TABDLY: u2 = 0,
        BSDLY: u1 = 0,
        VTDLY: u1 = 0,
        FFDLY: u1 = 0,
        PAGEOUT: bool = false,
        WRAP: bool = false,
        _: u14 = 0,
    },
    .haiku, .wasi, .emscripten => packed struct(u32) {
        OPOST: bool = false,
        OLCUC: bool = false,
        ONLCR: bool = false,
        OCRNL: bool = false,
        ONOCR: bool = false,
        ONLRET: bool = false,
        OFILL: bool = false,
        OFDEL: bool = false,
        NLDLY: u1 = 0,
        CRDLY: u2 = 0,
        TABDLY: u2 = 0,
        BSDLY: u1 = 0,
        VTDLY: u1 = 0,
        FFDLY: u1 = 0,
        _: u16 = 0,
    },
    else => void,
};

pub const CSIZE = switch (native_os) {
    .linux => linux.CSIZE,
    .haiku => enum(u1) { CS7, CS8 },
    else => enum(u2) { CS5, CS6, CS7, CS8 },
};

pub const tc_cflag_t = switch (native_os) {
    .linux => linux.tc_cflag_t,
    .macos, .ios, .tvos, .watchos, .visionos => packed struct(u64) {
        CIGNORE: bool = false,
        _1: u5 = 0,
        CSTOPB: bool = false,
        _7: u1 = 0,
        CSIZE: CSIZE = .CS5,
        _10: u1 = 0,
        CREAD: bool = false,
        PARENB: bool = false,
        PARODD: bool = false,
        HUPCL: bool = false,
        CLOCAL: bool = false,
        CCTS_OFLOW: bool = false,
        CRTS_IFLOW: bool = false,
        CDTR_IFLOW: bool = false,
        CDSR_OFLOW: bool = false,
        CCAR_OFLOW: bool = false,
        _: u43 = 0,
    },
    .freebsd => packed struct(u32) {
        CIGNORE: bool = false,
        _1: u7 = 0,
        CSIZE: CSIZE = .CS5,
        CSTOPB: bool = false,
        CREAD: bool = false,
        PARENB: bool = false,
        PARODD: bool = false,
        HUPCL: bool = false,
        CLOCAL: bool = false,
        CCTS_OFLOW: bool = false,
        CRTS_IFLOW: bool = false,
        CDTR_IFLOW: bool = false,
        CDSR_OFLOW: bool = false,
        CCAR_OFLOW: bool = false,
        CNO_RTSDTR: bool = false,
        _: u10 = 0,
    },
    .netbsd => packed struct(u32) {
        CIGNORE: bool = false,
        _1: u7 = 0,
        CSIZE: CSIZE = .CS5,
        CSTOPB: bool = false,
        CREAD: bool = false,
        PARENB: bool = false,
        PARODD: bool = false,
        HUPCL: bool = false,
        CLOCAL: bool = false,
        CRTSCTS: bool = false,
        CDTRCTS: bool = false,
        _18: u2 = 0,
        MDMBUF: bool = false,
        _: u11 = 0,
    },
    .dragonfly => packed struct(u32) {
        CIGNORE: bool = false,
        _1: u7 = 0,
        CSIZE: CSIZE = .CS5,
        CSTOPB: bool = false,
        CREAD: bool = false,
        PARENB: bool = false,
        PARODD: bool = false,
        HUPCL: bool = false,
        CLOCAL: bool = false,
        CCTS_OFLOW: bool = false,
        CRTS_IFLOW: bool = false,
        CDTR_IFLOW: bool = false,
        CDSR_OFLOW: bool = false,
        CCAR_OFLOW: bool = false,
        _: u11 = 0,
    },
    .openbsd => packed struct(u32) {
        CIGNORE: bool = false,
        _1: u7 = 0,
        CSIZE: CSIZE = .CS5,
        CSTOPB: bool = false,
        CREAD: bool = false,
        PARENB: bool = false,
        PARODD: bool = false,
        HUPCL: bool = false,
        CLOCAL: bool = false,
        CRTSCTS: bool = false,
        _17: u3 = 0,
        MDMBUF: bool = false,
        _: u11 = 0,
    },
    .haiku => packed struct(u32) {
        _0: u5 = 0,
        CSIZE: CSIZE = .CS7,
        CSTOPB: bool = false,
        CREAD: bool = false,
        PARENB: bool = false,
        PARODD: bool = false,
        HUPCL: bool = false,
        CLOCAL: bool = false,
        XLOBLK: bool = false,
        CTSFLOW: bool = false,
        RTSFLOW: bool = false,
        _: u17 = 0,
    },
    .solaris, .illumos => packed struct(u32) {
        _0: u4 = 0,
        CSIZE: CSIZE = .CS5,
        CSTOPB: bool = false,
        CREAD: bool = false,
        PARENB: bool = false,
        PARODD: bool = false,
        HUPCL: bool = false,
        CLOCAL: bool = false,
        RCV1EN: bool = false,
        XMT1EN: bool = false,
        LOBLK: bool = false,
        XCLUDE: bool = false,
        _16: u4 = 0,
        PAREXT: bool = false,
        CBAUDEXT: bool = false,
        CIBAUDEXT: bool = false,
        _23: u7 = 0,
        CRTSXOFF: bool = false,
        CRTSCTS: bool = false,
    },
    .wasi, .emscripten => packed struct(u32) {
        _0: u4 = 0,
        CSIZE: CSIZE = .CS5,
        CSTOPB: bool = false,
        CREAD: bool = false,
        PARENB: bool = false,
        PARODD: bool = false,
        HUPCL: bool = false,
        CLOCAL: bool = false,
        _: u20 = 0,
    },
    else => void,
};

pub const tc_lflag_t = switch (native_os) {
    .linux => linux.tc_lflag_t,
    .macos, .ios, .tvos, .watchos, .visionos => packed struct(u64) {
        ECHOKE: bool = false,
        ECHOE: bool = false,
        ECHOK: bool = false,
        ECHO: bool = false,
        ECHONL: bool = false,
        ECHOPRT: bool = false,
        ECHOCTL: bool = false,
        ISIG: bool = false,
        ICANON: bool = false,
        ALTWERASE: bool = false,
        IEXTEN: bool = false,
        EXTPROC: bool = false,
        _12: u10 = 0,
        TOSTOP: bool = false,
        FLUSHO: bool = false,
        _24: u1 = 0,
        NOKERNINFO: bool = false,
        _26: u3 = 0,
        PENDIN: bool = false,
        _30: u1 = 0,
        NOFLSH: bool = false,
        _: u32 = 0,
    },
    .netbsd, .freebsd, .dragonfly => packed struct(u32) {
        ECHOKE: bool = false,
        ECHOE: bool = false,
        ECHOK: bool = false,
        ECHO: bool = false,
        ECHONL: bool = false,
        ECHOPRT: bool = false,
        ECHOCTL: bool = false,
        ISIG: bool = false,
        ICANON: bool = false,
        ALTWERASE: bool = false,
        IEXTEN: bool = false,
        EXTPROC: bool = false,
        _12: u10 = 0,
        TOSTOP: bool = false,
        FLUSHO: bool = false,
        _24: u1 = 0,
        NOKERNINFO: bool = false,
        _26: u3 = 0,
        PENDIN: bool = false,
        _30: u1 = 0,
        NOFLSH: bool = false,
    },
    .openbsd => packed struct(u32) {
        ECHOKE: bool = false,
        ECHOE: bool = false,
        ECHOK: bool = false,
        ECHO: bool = false,
        ECHONL: bool = false,
        ECHOPRT: bool = false,
        ECHOCTL: bool = false,
        ISIG: bool = false,
        ICANON: bool = false,
        ALTWERASE: bool = false,
        IEXTEN: bool = false,
        EXTPROC: bool = false,
        _12: u10 = 0,
        TOSTOP: bool = false,
        FLUSHO: bool = false,
        XCASE: bool = false,
        NOKERNINFO: bool = false,
        _26: u3 = 0,
        PENDIN: bool = false,
        _30: u1 = 0,
        NOFLSH: bool = false,
    },
    .haiku => packed struct(u32) {
        ISIG: bool = false,
        ICANON: bool = false,
        XCASE: bool = false,
        ECHO: bool = false,
        ECHOE: bool = false,
        ECHOK: bool = false,
        ECHONL: bool = false,
        NOFLSH: bool = false,
        TOSTOP: bool = false,
        IEXTEN: bool = false,
        ECHOCTL: bool = false,
        ECHOPRT: bool = false,
        ECHOKE: bool = false,
        FLUSHO: bool = false,
        PENDIN: bool = false,
        _: u17 = 0,
    },
    .solaris, .illumos => packed struct(u32) {
        ISIG: bool = false,
        ICANON: bool = false,
        XCASE: bool = false,
        ECHO: bool = false,
        ECHOE: bool = false,
        ECHOK: bool = false,
        ECHONL: bool = false,
        NOFLSH: bool = false,
        TOSTOP: bool = false,
        ECHOCTL: bool = false,
        ECHOPRT: bool = false,
        ECHOKE: bool = false,
        DEFECHO: bool = false,
        FLUSHO: bool = false,
        PENDIN: bool = false,
        IEXTEN: bool = false,
        _: u16 = 0,
    },
    .wasi, .emscripten => packed struct(u32) {
        ISIG: bool = false,
        ICANON: bool = false,
        _2: u1 = 0,
        ECHO: bool = false,
        ECHOE: bool = false,
        ECHOK: bool = false,
        ECHONL: bool = false,
        NOFLSH: bool = false,
        TOSTOP: bool = false,
        _9: u6 = 0,
        IEXTEN: bool = false,
        _: u16 = 0,
    },
    else => void,
};

pub const speed_t = switch (native_os) {
    .linux => linux.speed_t,
    .macos, .ios, .tvos, .watchos, .visionos, .openbsd => enum(u64) {
        B0 = 0,
        B50 = 50,
        B75 = 75,
        B110 = 110,
        B134 = 134,
        B150 = 150,
        B200 = 200,
        B300 = 300,
        B600 = 600,
        B1200 = 1200,
        B1800 = 1800,
        B2400 = 2400,
        B4800 = 4800,
        B9600 = 9600,
        B19200 = 19200,
        B38400 = 38400,
        B7200 = 7200,
        B14400 = 14400,
        B28800 = 28800,
        B57600 = 57600,
        B76800 = 76800,
        B115200 = 115200,
        B230400 = 230400,
    },
    .freebsd, .netbsd => enum(c_uint) {
        B0 = 0,
        B50 = 50,
        B75 = 75,
        B110 = 110,
        B134 = 134,
        B150 = 150,
        B200 = 200,
        B300 = 300,
        B600 = 600,
        B1200 = 1200,
        B1800 = 1800,
        B2400 = 2400,
        B4800 = 4800,
        B9600 = 9600,
        B19200 = 19200,
        B38400 = 38400,
        B7200 = 7200,
        B14400 = 14400,
        B28800 = 28800,
        B57600 = 57600,
        B76800 = 76800,
        B115200 = 115200,
        B230400 = 230400,
        B460800 = 460800,
        B500000 = 500000,
        B921600 = 921600,
        B1000000 = 1000000,
        B1500000 = 1500000,
        B2000000 = 2000000,
        B2500000 = 2500000,
        B3000000 = 3000000,
        B3500000 = 3500000,
        B4000000 = 4000000,
    },
    .dragonfly => enum(c_uint) {
        B0 = 0,
        B50 = 50,
        B75 = 75,
        B110 = 110,
        B134 = 134,
        B150 = 150,
        B200 = 200,
        B300 = 300,
        B600 = 600,
        B1200 = 1200,
        B1800 = 1800,
        B2400 = 2400,
        B4800 = 4800,
        B9600 = 9600,
        B19200 = 19200,
        B38400 = 38400,
        B7200 = 7200,
        B14400 = 14400,
        B28800 = 28800,
        B57600 = 57600,
        B76800 = 76800,
        B115200 = 115200,
        B230400 = 230400,
        B460800 = 460800,
        B921600 = 921600,
    },
    .haiku => enum(u8) {
        B0 = 0x00,
        B50 = 0x01,
        B75 = 0x02,
        B110 = 0x03,
        B134 = 0x04,
        B150 = 0x05,
        B200 = 0x06,
        B300 = 0x07,
        B600 = 0x08,
        B1200 = 0x09,
        B1800 = 0x0A,
        B2400 = 0x0B,
        B4800 = 0x0C,
        B9600 = 0x0D,
        B19200 = 0x0E,
        B38400 = 0x0F,
        B57600 = 0x10,
        B115200 = 0x11,
        B230400 = 0x12,
        B31250 = 0x13,
    },
    .solaris, .illumos => enum(c_uint) {
        B0 = 0,
        B50 = 1,
        B75 = 2,
        B110 = 3,
        B134 = 4,
        B150 = 5,
        B200 = 6,
        B300 = 7,
        B600 = 8,
        B1200 = 9,
        B1800 = 10,
        B2400 = 11,
        B4800 = 12,
        B9600 = 13,
        B19200 = 14,
        B38400 = 15,
        B57600 = 16,
        B76800 = 17,
        B115200 = 18,
        B153600 = 19,
        B230400 = 20,
        B307200 = 21,
        B460800 = 22,
        B921600 = 23,
        B1000000 = 24,
        B1152000 = 25,
        B1500000 = 26,
        B2000000 = 27,
        B2500000 = 28,
        B3000000 = 29,
        B3500000 = 30,
        B4000000 = 31,
    },
    .emscripten, .wasi => enum(u32) {
        B0 = 0o0000000,
        B50 = 0o0000001,
        B75 = 0o0000002,
        B110 = 0o0000003,
        B134 = 0o0000004,
        B150 = 0o0000005,
        B200 = 0o0000006,
        B300 = 0o0000007,
        B600 = 0o0000010,
        B1200 = 0o0000011,
        B1800 = 0o0000012,
        B2400 = 0o0000013,
        B4800 = 0o0000014,
        B9600 = 0o0000015,
        B19200 = 0o0000016,
        B38400 = 0o0000017,

        B57600 = 0o0010001,
        B115200 = 0o0010002,
        B230400 = 0o0010003,
        B460800 = 0o0010004,
        B500000 = 0o0010005,
        B576000 = 0o0010006,
        B921600 = 0o0010007,
        B1000000 = 0o0010010,
        B1152000 = 0o0010011,
        B1500000 = 0o0010012,
        B2000000 = 0o0010013,
        B2500000 = 0o0010014,
        B3000000 = 0o0010015,
        B3500000 = 0o0010016,
        B4000000 = 0o0010017,
    },
    else => void,
};

pub const whence_t = if (native_os == .wasi) std.os.wasi.whence_t else c_int;

pub const sig_atomic_t = c_int;

/// maximum signal number + 1
pub const NSIG = switch (native_os) {
    .linux => linux.NSIG,
    .windows => 23,
    .haiku => 65,
    .netbsd, .freebsd => 32,
    .solaris, .illumos => 75,
    .openbsd => 33,
    else => {},
};

pub const MINSIGSTKSZ = switch (native_os) {
    .macos, .ios, .tvos, .watchos, .visionos => 32768,
    .freebsd => switch (builtin.cpu.arch) {
        .x86, .x86_64 => 2048,
        .arm, .aarch64 => 4096,
        else => @compileError("unsupported arch"),
    },
    .solaris, .illumos => 2048,
    .haiku, .netbsd => 8192,
    .openbsd => 1 << openbsd.MAX_PAGE_SHIFT,
    else => {},
};
pub const SIGSTKSZ = switch (native_os) {
    .macos, .ios, .tvos, .watchos, .visionos => 131072,
    .netbsd, .freebsd => MINSIGSTKSZ + 32768,
    .solaris, .illumos => 8192,
    .haiku => 16384,
    .openbsd => MINSIGSTKSZ + (1 << openbsd.MAX_PAGE_SHIFT) * 4,
    else => {},
};
pub const SS = switch (native_os) {
    .linux => linux.SS,
    .openbsd, .macos, .ios, .tvos, .watchos, .visionos, .netbsd, .freebsd => struct {
        pub const ONSTACK = 1;
        pub const DISABLE = 4;
    },
    .haiku, .solaris, .illumos => struct {
        pub const ONSTACK = 0x1;
        pub const DISABLE = 0x2;
    },
    else => void,
};

pub const EV = switch (native_os) {
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        /// add event to kq (implies enable)
        pub const ADD = 0x0001;
        /// delete event from kq
        pub const DELETE = 0x0002;
        /// enable event
        pub const ENABLE = 0x0004;
        /// disable event (not reported)
        pub const DISABLE = 0x0008;
        /// only report one occurrence
        pub const ONESHOT = 0x0010;
        /// clear event state after reporting
        pub const CLEAR = 0x0020;
        /// force immediate event output
        /// ... with or without ERROR
        /// ... use KEVENT_FLAG_ERROR_EVENTS
        ///     on syscalls supporting flags
        pub const RECEIPT = 0x0040;
        /// disable event after reporting
        pub const DISPATCH = 0x0080;
        /// unique kevent per udata value
        pub const UDATA_SPECIFIC = 0x0100;
        /// ... in combination with DELETE
        /// will defer delete until udata-specific
        /// event enabled. EINPROGRESS will be
        /// returned to indicate the deferral
        pub const DISPATCH2 = DISPATCH | UDATA_SPECIFIC;
        /// report that source has vanished
        /// ... only valid with DISPATCH2
        pub const VANISHED = 0x0200;
        /// reserved by system
        pub const SYSFLAGS = 0xF000;
        /// filter-specific flag
        pub const FLAG0 = 0x1000;
        /// filter-specific flag
        pub const FLAG1 = 0x2000;
        /// EOF detected
        pub const EOF = 0x8000;
        /// error, data contains errno
        pub const ERROR = 0x4000;
        pub const POLL = FLAG0;
        pub const OOBAND = FLAG1;
    },
    .dragonfly => struct {
        pub const ADD = 1;
        pub const DELETE = 2;
        pub const ENABLE = 4;
        pub const DISABLE = 8;
        pub const ONESHOT = 16;
        pub const CLEAR = 32;
        pub const RECEIPT = 64;
        pub const DISPATCH = 128;
        pub const NODATA = 4096;
        pub const FLAG1 = 8192;
        pub const ERROR = 16384;
        pub const EOF = 32768;
        pub const SYSFLAGS = 61440;
    },
    .netbsd => struct {
        /// add event to kq (implies enable)
        pub const ADD = 0x0001;
        /// delete event from kq
        pub const DELETE = 0x0002;
        /// enable event
        pub const ENABLE = 0x0004;
        /// disable event (not reported)
        pub const DISABLE = 0x0008;
        /// only report one occurrence
        pub const ONESHOT = 0x0010;
        /// clear event state after reporting
        pub const CLEAR = 0x0020;
        /// force immediate event output
        /// ... with or without ERROR
        /// ... use KEVENT_FLAG_ERROR_EVENTS
        ///     on syscalls supporting flags
        pub const RECEIPT = 0x0040;
        /// disable event after reporting
        pub const DISPATCH = 0x0080;
    },
    .freebsd => struct {
        /// add event to kq (implies enable)
        pub const ADD = 0x0001;
        /// delete event from kq
        pub const DELETE = 0x0002;
        /// enable event
        pub const ENABLE = 0x0004;
        /// disable event (not reported)
        pub const DISABLE = 0x0008;
        /// only report one occurrence
        pub const ONESHOT = 0x0010;
        /// clear event state after reporting
        pub const CLEAR = 0x0020;
        /// error, event data contains errno
        pub const ERROR = 0x4000;
        /// force immediate event output
        /// ... with or without ERROR
        /// ... use KEVENT_FLAG_ERROR_EVENTS
        ///     on syscalls supporting flags
        pub const RECEIPT = 0x0040;
        /// disable event after reporting
        pub const DISPATCH = 0x0080;
    },
    .openbsd => struct {
        pub const ADD = 0x0001;
        pub const DELETE = 0x0002;
        pub const ENABLE = 0x0004;
        pub const DISABLE = 0x0008;
        pub const ONESHOT = 0x0010;
        pub const CLEAR = 0x0020;
        pub const RECEIPT = 0x0040;
        pub const DISPATCH = 0x0080;
        pub const FLAG1 = 0x2000;
        pub const ERROR = 0x4000;
        pub const EOF = 0x8000;
    },
    .haiku => struct {
        /// add event to kq (implies enable)
        pub const ADD = 0x0001;
        /// delete event from kq
        pub const DELETE = 0x0002;
        /// enable event
        pub const ENABLE = 0x0004;
        /// disable event (not reported)
        pub const DISABLE = 0x0008;
        /// only report one occurrence
        pub const ONESHOT = 0x0010;
        /// clear event state after reporting
        pub const CLEAR = 0x0020;
        /// force immediate event output
        /// ... with or without ERROR
        /// ... use KEVENT_FLAG_ERROR_EVENTS
        ///     on syscalls supporting flags
        pub const RECEIPT = 0x0040;
        /// disable event after reporting
        pub const DISPATCH = 0x0080;
    },
    else => void,
};

pub const EVFILT = switch (native_os) {
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        pub const READ = -1;
        pub const WRITE = -2;
        /// attached to aio requests
        pub const AIO = -3;
        /// attached to vnodes
        pub const VNODE = -4;
        /// attached to struct proc
        pub const PROC = -5;
        /// attached to struct proc
        pub const SIGNAL = -6;
        /// timers
        pub const TIMER = -7;
        /// Mach portsets
        pub const MACHPORT = -8;
        /// Filesystem events
        pub const FS = -9;
        /// User events
        pub const USER = -10;
        /// Virtual memory events
        pub const VM = -12;
        /// Exception events
        pub const EXCEPT = -15;
        pub const SYSCOUNT = 17;
    },
    .haiku => struct {
        pub const READ = -1;
        pub const WRITE = -2;
        /// attached to aio requests
        pub const AIO = -3;
        /// attached to vnodes
        pub const VNODE = -4;
        /// attached to struct proc
        pub const PROC = -5;
        /// attached to struct proc
        pub const SIGNAL = -6;
        /// timers
        pub const TIMER = -7;
        /// Process descriptors
        pub const PROCDESC = -8;
        /// Filesystem events
        pub const FS = -9;
        pub const LIO = -10;
        /// User events
        pub const USER = -11;
        /// Sendfile events
        pub const SENDFILE = -12;
        pub const EMPTY = -13;
    },
    .dragonfly => struct {
        pub const FS = -10;
        pub const USER = -9;
        pub const EXCEPT = -8;
        pub const TIMER = -7;
        pub const SIGNAL = -6;
        pub const PROC = -5;
        pub const VNODE = -4;
        pub const AIO = -3;
        pub const WRITE = -2;
        pub const READ = -1;
        pub const SYSCOUNT = 10;
        pub const MARKER = 15;
    },
    .netbsd => struct {
        pub const READ = 0;
        pub const WRITE = 1;
        /// attached to aio requests
        pub const AIO = 2;
        /// attached to vnodes
        pub const VNODE = 3;
        /// attached to struct proc
        pub const PROC = 4;
        /// attached to struct proc
        pub const SIGNAL = 5;
        /// timers
        pub const TIMER = 6;
        /// Filesystem events
        pub const FS = 7;
        /// User events
        pub const USER = 1;
    },
    .freebsd => struct {
        pub const READ = -1;
        pub const WRITE = -2;
        /// attached to aio requests
        pub const AIO = -3;
        /// attached to vnodes
        pub const VNODE = -4;
        /// attached to struct proc
        pub const PROC = -5;
        /// attached to struct proc
        pub const SIGNAL = -6;
        /// timers
        pub const TIMER = -7;
        /// Process descriptors
        pub const PROCDESC = -8;
        /// Filesystem events
        pub const FS = -9;
        pub const LIO = -10;
        /// User events
        pub const USER = -11;
        /// Sendfile events
        pub const SENDFILE = -12;
        pub const EMPTY = -13;
    },
    .openbsd => struct {
        pub const READ = -1;
        pub const WRITE = -2;
        pub const AIO = -3;
        pub const VNODE = -4;
        pub const PROC = -5;
        pub const SIGNAL = -6;
        pub const TIMER = -7;
        pub const EXCEPT = -9;
    },
    else => void,
};

pub const NOTE = switch (native_os) {
    .macos, .ios, .tvos, .watchos, .visionos => struct {
        /// On input, TRIGGER causes the event to be triggered for output.
        pub const TRIGGER = 0x01000000;
        /// ignore input fflags
        pub const FFNOP = 0x00000000;
        /// and fflags
        pub const FFAND = 0x40000000;
        /// or fflags
        pub const FFOR = 0x80000000;
        /// copy fflags
        pub const FFCOPY = 0xc0000000;
        /// mask for operations
        pub const FFCTRLMASK = 0xc0000000;
        pub const FFLAGSMASK = 0x00ffffff;
        /// low water mark
        pub const LOWAT = 0x00000001;
        /// OOB data
        pub const OOB = 0x00000002;
        /// vnode was removed
        pub const DELETE = 0x00000001;
        /// data contents changed
        pub const WRITE = 0x00000002;
        /// size increased
        pub const EXTEND = 0x00000004;
        /// attributes changed
        pub const ATTRIB = 0x00000008;
        /// link count changed
        pub const LINK = 0x00000010;
        /// vnode was renamed
        pub const RENAME = 0x00000020;
        /// vnode access was revoked
        pub const REVOKE = 0x00000040;
        /// No specific vnode event: to test for EVFILT_READ      activation
        pub const NONE = 0x00000080;
        /// vnode was unlocked by flock(2)
        pub const FUNLOCK = 0x00000100;
        /// process exited
        pub const EXIT = 0x80000000;
        /// process forked
        pub const FORK = 0x40000000;
        /// process exec'd
        pub const EXEC = 0x20000000;
        /// shared with EVFILT_SIGNAL
        pub const SIGNAL = 0x08000000;
        /// exit status to be returned, valid for child       process only
        pub const EXITSTATUS = 0x04000000;
        /// provide details on reasons for exit
        pub const EXIT_DETAIL = 0x02000000;
        /// mask for signal & exit status
        pub const PDATAMASK = 0x000fffff;
        pub const PCTRLMASK = (~PDATAMASK);
        pub const EXIT_DETAIL_MASK = 0x00070000;
        pub const EXIT_DECRYPTFAIL = 0x00010000;
        pub const EXIT_MEMORY = 0x00020000;
        pub const EXIT_CSERROR = 0x00040000;
        /// will react on memory          pressure
        pub const VM_PRESSURE = 0x80000000;
        /// will quit on memory       pressure, possibly after cleaning up dirty state
        pub const VM_PRESSURE_TERMINATE = 0x40000000;
        /// will quit immediately on      memory pressure
        pub const VM_PRESSURE_SUDDEN_TERMINATE = 0x20000000;
        /// there was an error
        pub const VM_ERROR = 0x10000000;
        /// data is seconds
        pub const SECONDS = 0x00000001;
        /// data is microseconds
        pub const USECONDS = 0x00000002;
        /// data is nanoseconds
        pub const NSECONDS = 0x00000004;
        /// absolute timeout
        pub const ABSOLUTE = 0x00000008;
        /// ext[1] holds leeway for power aware timers
        pub const LEEWAY = 0x00000010;
        /// system does minimal timer coalescing
        pub const CRITICAL = 0x00000020;
        /// system does maximum timer coalescing
        pub const BACKGROUND = 0x00000040;
        pub const MACH_CONTINUOUS_TIME = 0x00000080;
        /// data is mach absolute time units
        pub const MACHTIME = 0x00000100;
    },
    .dragonfly => struct {
        pub const FFNOP = 0;
        pub const TRACK = 1;
        pub const DELETE = 1;
        pub const LOWAT = 1;
        pub const TRACKERR = 2;
        pub const OOB = 2;
        pub const WRITE = 2;
        pub const EXTEND = 4;
        pub const CHILD = 4;
        pub const ATTRIB = 8;
        pub const LINK = 16;
        pub const RENAME = 32;
        pub const REVOKE = 64;
        pub const PDATAMASK = 1048575;
        pub const FFLAGSMASK = 16777215;
        pub const TRIGGER = 16777216;
        pub const EXEC = 536870912;
        pub const FFAND = 1073741824;
        pub const FORK = 1073741824;
        pub const EXIT = 2147483648;
        pub const FFOR = 2147483648;
        pub const FFCTRLMASK = 3221225472;
        pub const FFCOPY = 3221225472;
        pub const PCTRLMASK = 4026531840;
    },
    .netbsd => struct {
        /// On input, TRIGGER causes the event to be triggered for output.
        pub const TRIGGER = 0x08000000;
        /// low water mark
        pub const LOWAT = 0x00000001;
        /// vnode was removed
        pub const DELETE = 0x00000001;
        /// data contents changed
        pub const WRITE = 0x00000002;
        /// size increased
        pub const EXTEND = 0x00000004;
        /// attributes changed
        pub const ATTRIB = 0x00000008;
        /// link count changed
        pub const LINK = 0x00000010;
        /// vnode was renamed
        pub const RENAME = 0x00000020;
        /// vnode access was revoked
        pub const REVOKE = 0x00000040;
        /// process exited
        pub const EXIT = 0x80000000;
        /// process forked
        pub const FORK = 0x40000000;
        /// process exec'd
        pub const EXEC = 0x20000000;
        /// mask for signal & exit status
        pub const PDATAMASK = 0x000fffff;
        pub const PCTRLMASK = 0xf0000000;
    },
    .freebsd => struct {
        /// On input, TRIGGER causes the event to be triggered for output.
        pub const TRIGGER = 0x01000000;
        /// ignore input fflags
        pub const FFNOP = 0x00000000;
        /// and fflags
        pub const FFAND = 0x40000000;
        /// or fflags
        pub const FFOR = 0x80000000;
        /// copy fflags
        pub const FFCOPY = 0xc0000000;
        /// mask for operations
        pub const FFCTRLMASK = 0xc0000000;
        pub const FFLAGSMASK = 0x00ffffff;
        /// low water mark
        pub const LOWAT = 0x00000001;
        /// behave like poll()
        pub const FILE_POLL = 0x00000002;
        /// vnode was removed
        pub const DELETE = 0x00000001;
        /// data contents changed
        pub const WRITE = 0x00000002;
        /// size increased
        pub const EXTEND = 0x00000004;
        /// attributes changed
        pub const ATTRIB = 0x00000008;
        /// link count changed
        pub const LINK = 0x00000010;
        /// vnode was renamed
        pub const RENAME = 0x00000020;
        /// vnode access was revoked
        pub const REVOKE = 0x00000040;
        /// vnode was opened
        pub const OPEN = 0x00000080;
        /// file closed, fd did not allow write
        pub const CLOSE = 0x00000100;
        /// file closed, fd did allow write
        pub const CLOSE_WRITE = 0x00000200;
        /// file was read
        pub const READ = 0x00000400;
        /// process exited
        pub const EXIT = 0x80000000;
        /// process forked
        pub const FORK = 0x40000000;
        /// process exec'd
        pub const EXEC = 0x20000000;
        /// mask for signal & exit status
        pub const PDATAMASK = 0x000fffff;
        pub const PCTRLMASK = (~PDATAMASK);
        /// data is seconds
        pub const SECONDS = 0x00000001;
        /// data is milliseconds
        pub const MSECONDS = 0x00000002;
        /// data is microseconds
        pub const USECONDS = 0x00000004;
        /// data is nanoseconds
        pub const NSECONDS = 0x00000008;
        /// timeout is absolute
        pub const ABSTIME = 0x00000010;
    },
    .openbsd => struct {
        // data/hint flags for EVFILT.{READ|WRITE}
        pub const LOWAT = 0x0001;
        pub const EOF = 0x0002;
        // data/hint flags for EVFILT.EXCEPT and EVFILT.{READ|WRITE}
        pub const OOB = 0x0004;
        // data/hint flags for EVFILT.VNODE
        pub const DELETE = 0x0001;
        pub const WRITE = 0x0002;
        pub const EXTEND = 0x0004;
        pub const ATTRIB = 0x0008;
        pub const LINK = 0x0010;
        pub const RENAME = 0x0020;
        pub const REVOKE = 0x0040;
        pub const TRUNCATE = 0x0080;
        // data/hint flags for EVFILT.PROC
        pub const EXIT = 0x80000000;
        pub const FORK = 0x40000000;
        pub const EXEC = 0x20000000;
        pub const PDATAMASK = 0x000fffff;
        pub const PCTRLMASK = 0xf0000000;
        pub const TRACK = 0x00000001;
        pub const TRACKERR = 0x00000002;
        pub const CHILD = 0x00000004;
        // data/hint flags for EVFILT.DEVICE
        pub const CHANGE = 0x00000001;
    },
    else => void,
};

// Unix-like systems
pub const DIR = opaque {};
pub extern "c" fn opendir(pathname: [*:0]const u8) ?*DIR;
pub extern "c" fn fdopendir(fd: c_int) ?*DIR;
pub extern "c" fn rewinddir(dp: *DIR) void;
pub extern "c" fn closedir(dp: *DIR) c_int;
pub extern "c" fn telldir(dp: *DIR) c_long;
pub extern "c" fn seekdir(dp: *DIR, loc: c_long) void;

pub extern "c" fn sigwait(set: ?*sigset_t, sig: ?*c_int) c_int;

pub extern "c" fn alarm(seconds: c_uint) c_uint;

pub const close = switch (native_os) {
    .macos, .ios, .tvos, .watchos, .visionos => darwin.@"close$NOCANCEL",
    else => private.close,
};

pub const clock_getres = switch (native_os) {
    .netbsd => private.__clock_getres50,
    else => private.clock_getres,
};

pub const clock_gettime = switch (native_os) {
    .netbsd => private.__clock_gettime50,
    else => private.clock_gettime,
};

pub const fstat = switch (native_os) {
    .macos => switch (native_arch) {
        .x86_64 => private.@"fstat$INODE64",
        else => private.fstat,
    },
    .netbsd => private.__fstat50,
    else => private.fstat,
};

pub const fstatat = switch (native_os) {
    .macos => switch (native_arch) {
        .x86_64 => private.@"fstatat$INODE64",
        else => private.fstatat,
    },
    else => private.fstatat,
};

pub extern "c" fn getpwnam(name: [*:0]const u8) ?*passwd;
pub extern "c" fn getpwuid(uid: uid_t) ?*passwd;
pub extern "c" fn getrlimit64(resource: rlimit_resource, rlim: *rlimit) c_int;
pub extern "c" fn lseek64(fd: fd_t, offset: i64, whence: c_int) i64;
pub extern "c" fn mmap64(addr: ?*align(std.mem.page_size) anyopaque, len: usize, prot: c_uint, flags: c_uint, fd: fd_t, offset: i64) *anyopaque;
pub extern "c" fn open64(path: [*:0]const u8, oflag: O, ...) c_int;
pub extern "c" fn openat64(fd: c_int, path: [*:0]const u8, oflag: O, ...) c_int;
pub extern "c" fn pread64(fd: fd_t, buf: [*]u8, nbyte: usize, offset: i64) isize;
pub extern "c" fn preadv64(fd: c_int, iov: [*]const iovec, iovcnt: c_uint, offset: i64) isize;
pub extern "c" fn pwrite64(fd: fd_t, buf: [*]const u8, nbyte: usize, offset: i64) isize;
pub extern "c" fn pwritev64(fd: c_int, iov: [*]const iovec_const, iovcnt: c_uint, offset: i64) isize;
pub extern "c" fn sendfile64(out_fd: fd_t, in_fd: fd_t, offset: ?*i64, count: usize) isize;
pub extern "c" fn setrlimit64(resource: rlimit_resource, rlim: *const rlimit) c_int;

pub const arc4random_buf = switch (native_os) {
    .dragonfly, .netbsd, .freebsd, .solaris, .openbsd, .macos, .ios, .tvos, .watchos, .visionos => private.arc4random_buf,
    else => {},
};
pub const getentropy = switch (native_os) {
    .emscripten => private.getentropy,
    else => {},
};
pub const getrandom = switch (native_os) {
    .freebsd => private.getrandom,
    .linux => if (versionCheck(.{ .major = 2, .minor = 25, .patch = 0 })) private.getrandom else {},
    else => {},
};

pub extern "c" fn sched_getaffinity(pid: c_int, size: usize, set: *cpu_set_t) c_int;
pub extern "c" fn eventfd(initval: c_uint, flags: c_uint) c_int;

pub extern "c" fn epoll_ctl(epfd: fd_t, op: c_uint, fd: fd_t, event: ?*epoll_event) c_int;
pub extern "c" fn epoll_create1(flags: c_uint) c_int;
pub extern "c" fn epoll_wait(epfd: fd_t, events: [*]epoll_event, maxevents: c_uint, timeout: c_int) c_int;
pub extern "c" fn epoll_pwait(
    epfd: fd_t,
    events: [*]epoll_event,
    maxevents: c_int,
    timeout: c_int,
    sigmask: *const sigset_t,
) c_int;

pub extern "c" fn timerfd_create(clockid: clockid_t, flags: c_int) c_int;
pub extern "c" fn timerfd_settime(
    fd: c_int,
    flags: c_int,
    new_value: *const itimerspec,
    old_value: ?*itimerspec,
) c_int;
pub extern "c" fn timerfd_gettime(fd: c_int, curr_value: *itimerspec) c_int;

pub extern "c" fn inotify_init1(flags: c_uint) c_int;
pub extern "c" fn inotify_add_watch(fd: fd_t, pathname: [*:0]const u8, mask: u32) c_int;
pub extern "c" fn inotify_rm_watch(fd: fd_t, wd: c_int) c_int;

pub extern "c" fn fstat64(fd: fd_t, buf: *Stat) c_int;
pub extern "c" fn fstatat64(dirfd: fd_t, noalias path: [*:0]const u8, noalias stat_buf: *Stat, flags: u32) c_int;
pub extern "c" fn fallocate64(fd: fd_t, mode: c_int, offset: off_t, len: off_t) c_int;
pub extern "c" fn fopen64(noalias filename: [*:0]const u8, noalias modes: [*:0]const u8) ?*FILE;
pub extern "c" fn ftruncate64(fd: c_int, length: off_t) c_int;
pub extern "c" fn fallocate(fd: fd_t, mode: c_int, offset: off_t, len: off_t) c_int;
pub const sendfile = switch (native_os) {
    .freebsd => freebsd.sendfile,
    .macos, .ios, .tvos, .watchos, .visionos => darwin.sendfile,
    .linux => private.sendfile,
    else => {},
};
/// See std.elf for constants for this
pub extern "c" fn getauxval(__type: c_ulong) c_ulong;

pub extern "c" fn dl_iterate_phdr(callback: dl_iterate_phdr_callback, data: ?*anyopaque) c_int;

pub const sigaltstack = switch (native_os) {
    .netbsd => private.__sigaltstack14,
    else => private.sigaltstack,
};

pub extern "c" fn memfd_create(name: [*:0]const u8, flags: c_uint) c_int;
pub const pipe2 = switch (native_os) {
    .dragonfly, .emscripten, .netbsd, .freebsd, .solaris, .illumos, .openbsd, .linux => private.pipe2,
    else => {},
};
pub const copy_file_range = switch (native_os) {
    .linux => private.copy_file_range,
    .freebsd => freebsd.copy_file_range,
    else => {},
};

pub extern "c" fn signalfd(fd: fd_t, mask: *const sigset_t, flags: u32) c_int;

pub extern "c" fn prlimit(pid: pid_t, resource: rlimit_resource, new_limit: *const rlimit, old_limit: *rlimit) c_int;
pub extern "c" fn mincore(
    addr: *align(std.mem.page_size) anyopaque,
    length: usize,
    vec: [*]u8,
) c_int;

pub extern "c" fn madvise(
    addr: *align(std.mem.page_size) anyopaque,
    length: usize,
    advice: u32,
) c_int;

pub const getdirentries = switch (native_os) {
    .macos, .ios, .tvos, .watchos, .visionos => private.__getdirentries64,
    else => private.getdirentries,
};

pub const getdents = switch (native_os) {
    .netbsd => private.__getdents30,
    else => private.getdents,
};

pub const getrusage = switch (native_os) {
    .netbsd => private.__getrusage50,
    else => private.getrusage,
};

pub const gettimeofday = switch (native_os) {
    .netbsd => private.__gettimeofday50,
    else => private.gettimeofday,
};

pub const msync = switch (native_os) {
    .netbsd => private.__msync13,
    else => private.msync,
};

pub const nanosleep = switch (native_os) {
    .netbsd => private.__nanosleep50,
    else => private.nanosleep,
};

pub const readdir = switch (native_os) {
    .macos => switch (native_arch) {
        .x86_64 => private.@"readdir$INODE64",
        else => private.readdir,
    },
    .windows => {},
    else => private.readdir,
};

pub const realpath = switch (native_os) {
    .macos, .ios, .tvos, .watchos, .visionos => private.@"realpath$DARWIN_EXTSN",
    else => private.realpath,
};

pub const sched_yield = switch (native_os) {
    .netbsd => private.__libc_thr_yield,
    else => private.sched_yield,
};

pub const sigaction = switch (native_os) {
    .netbsd => private.__sigaction14,
    else => private.sigaction,
};

pub const sigfillset = switch (native_os) {
    .netbsd => private.__sigfillset14,
    else => private.sigfillset,
};

pub const sigprocmask = switch (native_os) {
    .netbsd => private.__sigprocmask14,
    else => private.sigprocmask,
};

pub const socket = switch (native_os) {
    .netbsd => private.__socket30,
    else => private.socket,
};

pub const stat = switch (native_os) {
    .macos => switch (native_arch) {
        .x86_64 => private.@"stat$INODE64",
        else => private.stat,
    },
    else => private.stat,
};

pub const _msize = switch (native_os) {
    .windows => private._msize,
    else => {},
};
pub const malloc_size = switch (native_os) {
    .macos, .ios, .tvos, .watchos, .visionos => private.malloc_size,
    else => {},
};
pub const malloc_usable_size = switch (native_os) {
    .freebsd, .linux => private.malloc_usable_size,
    else => {},
};
pub const posix_memalign = switch (native_os) {
    .dragonfly, .netbsd, .freebsd, .solaris, .openbsd, .linux, .macos, .ios, .tvos, .watchos, .visionos => private.posix_memalign,
    else => {},
};

pub const sf_hdtr = switch (native_os) {
    .freebsd, .macos, .ios, .tvos, .watchos, .visionos => extern struct {
        headers: [*]const iovec_const,
        hdr_cnt: c_int,
        trailers: [*]const iovec_const,
        trl_cnt: c_int,
    },
    else => void,
};

pub const flock = switch (native_os) {
    .windows, .wasi => {},
    else => private.flock,
};

pub extern "c" var environ: [*:null]?[*:0]u8;

pub extern "c" fn fopen(noalias filename: [*:0]const u8, noalias modes: [*:0]const u8) ?*FILE;
pub extern "c" fn fclose(stream: *FILE) c_int;
pub extern "c" fn fwrite(noalias ptr: [*]const u8, size_of_type: usize, item_count: usize, noalias stream: *FILE) usize;
pub extern "c" fn fread(noalias ptr: [*]u8, size_of_type: usize, item_count: usize, noalias stream: *FILE) usize;

pub extern "c" fn printf(format: [*:0]const u8, ...) c_int;
pub extern "c" fn abort() noreturn;
pub extern "c" fn exit(code: c_int) noreturn;
pub extern "c" fn _exit(code: c_int) noreturn;
pub extern "c" fn isatty(fd: fd_t) c_int;
pub extern "c" fn lseek(fd: fd_t, offset: off_t, whence: whence_t) off_t;
pub extern "c" fn open(path: [*:0]const u8, oflag: O, ...) c_int;
pub extern "c" fn openat(fd: c_int, path: [*:0]const u8, oflag: O, ...) c_int;
pub extern "c" fn ftruncate(fd: c_int, length: off_t) c_int;
pub extern "c" fn raise(sig: c_int) c_int;
pub extern "c" fn read(fd: fd_t, buf: [*]u8, nbyte: usize) isize;
pub extern "c" fn readv(fd: c_int, iov: [*]const iovec, iovcnt: c_uint) isize;
pub extern "c" fn pread(fd: fd_t, buf: [*]u8, nbyte: usize, offset: off_t) isize;
pub extern "c" fn preadv(fd: c_int, iov: [*]const iovec, iovcnt: c_uint, offset: off_t) isize;
pub extern "c" fn writev(fd: c_int, iov: [*]const iovec_const, iovcnt: c_uint) isize;
pub extern "c" fn pwritev(fd: c_int, iov: [*]const iovec_const, iovcnt: c_uint, offset: off_t) isize;
pub extern "c" fn write(fd: fd_t, buf: [*]const u8, nbyte: usize) isize;
pub extern "c" fn pwrite(fd: fd_t, buf: [*]const u8, nbyte: usize, offset: off_t) isize;
pub extern "c" fn mmap(addr: ?*align(page_size) anyopaque, len: usize, prot: c_uint, flags: MAP, fd: fd_t, offset: off_t) *anyopaque;
pub extern "c" fn munmap(addr: *align(page_size) const anyopaque, len: usize) c_int;
pub extern "c" fn mprotect(addr: *align(page_size) anyopaque, len: usize, prot: c_uint) c_int;
pub extern "c" fn link(oldpath: [*:0]const u8, newpath: [*:0]const u8) c_int;
pub extern "c" fn linkat(oldfd: fd_t, oldpath: [*:0]const u8, newfd: fd_t, newpath: [*:0]const u8, flags: c_int) c_int;
pub extern "c" fn unlink(path: [*:0]const u8) c_int;
pub extern "c" fn unlinkat(dirfd: fd_t, path: [*:0]const u8, flags: c_uint) c_int;
pub extern "c" fn getcwd(buf: [*]u8, size: usize) ?[*]u8;
pub extern "c" fn waitpid(pid: pid_t, status: ?*c_int, options: c_int) pid_t;
pub extern "c" fn wait4(pid: pid_t, status: ?*c_int, options: c_int, ru: ?*rusage) pid_t;
pub const fork = switch (native_os) {
    .dragonfly,
    .freebsd,
    .ios,
    .linux,
    .macos,
    .netbsd,
    .openbsd,
    .solaris,
    .illumos,
    .tvos,
    .watchos,
    .visionos,
    .haiku,
    => private.fork,
    else => {},
};
pub extern "c" fn access(path: [*:0]const u8, mode: c_uint) c_int;
pub extern "c" fn faccessat(dirfd: fd_t, path: [*:0]const u8, mode: c_uint, flags: c_uint) c_int;
pub extern "c" fn pipe(fds: *[2]fd_t) c_int;
pub extern "c" fn mkdir(path: [*:0]const u8, mode: c_uint) c_int;
pub extern "c" fn mkdirat(dirfd: fd_t, path: [*:0]const u8, mode: u32) c_int;
pub extern "c" fn symlink(existing: [*:0]const u8, new: [*:0]const u8) c_int;
pub extern "c" fn symlinkat(oldpath: [*:0]const u8, newdirfd: fd_t, newpath: [*:0]const u8) c_int;
pub extern "c" fn rename(old: [*:0]const u8, new: [*:0]const u8) c_int;
pub extern "c" fn renameat(olddirfd: fd_t, old: [*:0]const u8, newdirfd: fd_t, new: [*:0]const u8) c_int;
pub extern "c" fn chdir(path: [*:0]const u8) c_int;
pub extern "c" fn fchdir(fd: fd_t) c_int;
pub extern "c" fn execve(path: [*:0]const u8, argv: [*:null]const ?[*:0]const u8, envp: [*:null]const ?[*:0]const u8) c_int;
pub extern "c" fn dup(fd: fd_t) c_int;
pub extern "c" fn dup2(old_fd: fd_t, new_fd: fd_t) c_int;
pub extern "c" fn dup3(old: c_int, new: c_int, flags: c_uint) c_int;
pub extern "c" fn readlink(noalias path: [*:0]const u8, noalias buf: [*]u8, bufsize: usize) isize;
pub extern "c" fn readlinkat(dirfd: fd_t, noalias path: [*:0]const u8, noalias buf: [*]u8, bufsize: usize) isize;
pub extern "c" fn chmod(path: [*:0]const u8, mode: mode_t) c_int;
pub extern "c" fn fchmod(fd: fd_t, mode: mode_t) c_int;
pub extern "c" fn fchmodat(fd: fd_t, path: [*:0]const u8, mode: mode_t, flags: c_uint) c_int;
pub extern "c" fn fchown(fd: fd_t, owner: uid_t, group: gid_t) c_int;
pub extern "c" fn umask(mode: mode_t) mode_t;

pub extern "c" fn rmdir(path: [*:0]const u8) c_int;
pub extern "c" fn getenv(name: [*:0]const u8) ?[*:0]u8;
pub extern "c" fn sysctl(name: [*]const c_int, namelen: c_uint, oldp: ?*anyopaque, oldlenp: ?*usize, newp: ?*anyopaque, newlen: usize) c_int;
pub extern "c" fn sysctlbyname(name: [*:0]const u8, oldp: ?*anyopaque, oldlenp: ?*usize, newp: ?*anyopaque, newlen: usize) c_int;
pub extern "c" fn sysctlnametomib(name: [*:0]const u8, mibp: ?*c_int, sizep: ?*usize) c_int;
pub extern "c" fn tcgetattr(fd: fd_t, termios_p: *termios) c_int;
pub extern "c" fn tcsetattr(fd: fd_t, optional_action: TCSA, termios_p: *const termios) c_int;
pub extern "c" fn fcntl(fd: fd_t, cmd: c_int, ...) c_int;
pub extern "c" fn ioctl(fd: fd_t, request: c_int, ...) c_int;
pub extern "c" fn uname(buf: *utsname) c_int;

pub extern "c" fn gethostname(name: [*]u8, len: usize) c_int;
pub extern "c" fn shutdown(socket: fd_t, how: c_int) c_int;
pub extern "c" fn bind(socket: fd_t, address: ?*const sockaddr, address_len: socklen_t) c_int;
pub extern "c" fn socketpair(domain: c_uint, sock_type: c_uint, protocol: c_uint, sv: *[2]fd_t) c_int;
pub extern "c" fn listen(sockfd: fd_t, backlog: c_uint) c_int;
pub extern "c" fn getsockname(sockfd: fd_t, noalias addr: *sockaddr, noalias addrlen: *socklen_t) c_int;
pub extern "c" fn getpeername(sockfd: fd_t, noalias addr: *sockaddr, noalias addrlen: *socklen_t) c_int;
pub extern "c" fn connect(sockfd: fd_t, sock_addr: *const sockaddr, addrlen: socklen_t) c_int;
pub extern "c" fn accept(sockfd: fd_t, noalias addr: ?*sockaddr, noalias addrlen: ?*socklen_t) c_int;
pub extern "c" fn accept4(sockfd: fd_t, noalias addr: ?*sockaddr, noalias addrlen: ?*socklen_t, flags: c_uint) c_int;
pub extern "c" fn getsockopt(sockfd: fd_t, level: i32, optname: u32, noalias optval: ?*anyopaque, noalias optlen: *socklen_t) c_int;
pub extern "c" fn setsockopt(sockfd: fd_t, level: i32, optname: u32, optval: ?*const anyopaque, optlen: socklen_t) c_int;
pub extern "c" fn send(sockfd: fd_t, buf: *const anyopaque, len: usize, flags: u32) isize;
pub extern "c" fn sendto(
    sockfd: fd_t,
    buf: *const anyopaque,
    len: usize,
    flags: u32,
    dest_addr: ?*const sockaddr,
    addrlen: socklen_t,
) isize;
pub extern "c" fn sendmsg(sockfd: fd_t, msg: *const msghdr_const, flags: u32) isize;

pub extern "c" fn recv(
    sockfd: fd_t,
    arg1: ?*anyopaque,
    arg2: usize,
    arg3: c_int,
) if (native_os == .windows) c_int else isize;
pub extern "c" fn recvfrom(
    sockfd: fd_t,
    noalias buf: *anyopaque,
    len: usize,
    flags: u32,
    noalias src_addr: ?*sockaddr,
    noalias addrlen: ?*socklen_t,
) if (native_os == .windows) c_int else isize;
pub extern "c" fn recvmsg(sockfd: fd_t, msg: *msghdr, flags: u32) isize;

pub extern "c" fn kill(pid: pid_t, sig: c_int) c_int;

pub extern "c" fn setuid(uid: uid_t) c_int;
pub extern "c" fn setgid(gid: gid_t) c_int;
pub extern "c" fn seteuid(euid: uid_t) c_int;
pub extern "c" fn setegid(egid: gid_t) c_int;
pub extern "c" fn setreuid(ruid: uid_t, euid: uid_t) c_int;
pub extern "c" fn setregid(rgid: gid_t, egid: gid_t) c_int;
pub extern "c" fn setresuid(ruid: uid_t, euid: uid_t, suid: uid_t) c_int;
pub extern "c" fn setresgid(rgid: gid_t, egid: gid_t, sgid: gid_t) c_int;
pub extern "c" fn setpgid(pid: pid_t, pgid: pid_t) c_int;

pub extern "c" fn malloc(usize) ?*anyopaque;
pub extern "c" fn realloc(?*anyopaque, usize) ?*anyopaque;
pub extern "c" fn free(?*anyopaque) void;

pub extern "c" fn futimes(fd: fd_t, times: *[2]timeval) c_int;
pub extern "c" fn utimes(path: [*:0]const u8, times: *[2]timeval) c_int;

pub extern "c" fn utimensat(dirfd: fd_t, pathname: [*:0]const u8, times: *[2]timespec, flags: u32) c_int;
pub extern "c" fn futimens(fd: fd_t, times: *const [2]timespec) c_int;

pub extern "c" fn pthread_create(
    noalias newthread: *pthread_t,
    noalias attr: ?*const pthread_attr_t,
    start_routine: *const fn (?*anyopaque) callconv(.C) ?*anyopaque,
    noalias arg: ?*anyopaque,
) E;
pub extern "c" fn pthread_attr_init(attr: *pthread_attr_t) E;
pub extern "c" fn pthread_attr_setstack(attr: *pthread_attr_t, stackaddr: *anyopaque, stacksize: usize) E;
pub extern "c" fn pthread_attr_setstacksize(attr: *pthread_attr_t, stacksize: usize) E;
pub extern "c" fn pthread_attr_setguardsize(attr: *pthread_attr_t, guardsize: usize) E;
pub extern "c" fn pthread_attr_destroy(attr: *pthread_attr_t) E;
pub extern "c" fn pthread_self() pthread_t;
pub extern "c" fn pthread_join(thread: pthread_t, arg_return: ?*?*anyopaque) E;
pub extern "c" fn pthread_detach(thread: pthread_t) E;
pub extern "c" fn pthread_atfork(
    prepare: ?*const fn () callconv(.C) void,
    parent: ?*const fn () callconv(.C) void,
    child: ?*const fn () callconv(.C) void,
) c_int;
pub extern "c" fn pthread_key_create(
    key: *pthread_key_t,
    destructor: ?*const fn (value: *anyopaque) callconv(.C) void,
) E;
pub extern "c" fn pthread_key_delete(key: pthread_key_t) E;
pub extern "c" fn pthread_getspecific(key: pthread_key_t) ?*anyopaque;
pub extern "c" fn pthread_setspecific(key: pthread_key_t, value: ?*anyopaque) c_int;
pub extern "c" fn pthread_sigmask(how: c_int, set: *const sigset_t, oldset: *sigset_t) c_int;
pub const pthread_setname_np = switch (native_os) {
    .macos, .ios, .tvos, .watchos, .visionos => darwin.pthread_setname_np,
    .solaris, .illumos => solaris.pthread_setname_np,
    .netbsd => netbsd.pthread_setname_np,
    else => private.pthread_setname_np,
};

pub extern "c" fn pthread_getname_np(thread: pthread_t, name: [*:0]u8, len: usize) c_int;
pub const pthread_threadid_np = switch (native_os) {
    .macos, .ios, .tvos, .watchos, .visionos => private.pthread_threadid_np,
    else => {},
};

pub extern "c" fn sem_init(sem: *sem_t, pshared: c_int, value: c_uint) c_int;
pub extern "c" fn sem_destroy(sem: *sem_t) c_int;
pub extern "c" fn sem_open(name: [*:0]const u8, flag: c_int, mode: mode_t, value: c_uint) *sem_t;
pub extern "c" fn sem_close(sem: *sem_t) c_int;
pub extern "c" fn sem_post(sem: *sem_t) c_int;
pub extern "c" fn sem_wait(sem: *sem_t) c_int;
pub extern "c" fn sem_trywait(sem: *sem_t) c_int;
pub extern "c" fn sem_timedwait(sem: *sem_t, abs_timeout: *const timespec) c_int;
pub extern "c" fn sem_getvalue(sem: *sem_t, sval: *c_int) c_int;

pub extern "c" fn shm_open(name: [*:0]const u8, flag: c_int, mode: mode_t) c_int;
pub extern "c" fn shm_unlink(name: [*:0]const u8) c_int;

pub extern "c" fn kqueue() c_int;
pub extern "c" fn kevent(
    kq: c_int,
    changelist: [*]const Kevent,
    nchanges: c_int,
    eventlist: [*]Kevent,
    nevents: c_int,
    timeout: ?*const timespec,
) c_int;

pub extern "c" fn port_create() port_t;
pub extern "c" fn port_associate(
    port: port_t,
    source: u32,
    object: usize,
    events: u32,
    user_var: ?*anyopaque,
) c_int;
pub extern "c" fn port_dissociate(port: port_t, source: u32, object: usize) c_int;
pub extern "c" fn port_send(port: port_t, events: u32, user_var: ?*anyopaque) c_int;
pub extern "c" fn port_sendn(
    ports: [*]port_t,
    errors: []u32,
    num_ports: u32,
    events: u32,
    user_var: ?*anyopaque,
) c_int;
pub extern "c" fn port_get(port: port_t, event: *port_event, timeout: ?*timespec) c_int;
pub extern "c" fn port_getn(
    port: port_t,
    event_list: []port_event,
    max_events: u32,
    events_retrieved: *u32,
    timeout: ?*timespec,
) c_int;
pub extern "c" fn port_alert(port: port_t, flags: u32, events: u32, user_var: ?*anyopaque) c_int;

pub extern "c" fn getaddrinfo(
    noalias node: ?[*:0]const u8,
    noalias service: ?[*:0]const u8,
    noalias hints: ?*const addrinfo,
    /// On Linux, `res` will not be modified on error and `freeaddrinfo` will
    /// potentially crash if you pass it an undefined pointer
    noalias res: *?*addrinfo,
) EAI;

pub extern "c" fn freeaddrinfo(res: *addrinfo) void;

pub extern "c" fn getnameinfo(
    noalias addr: *const sockaddr,
    addrlen: socklen_t,
    noalias host: [*]u8,
    hostlen: socklen_t,
    noalias serv: [*]u8,
    servlen: socklen_t,
    flags: u32,
) EAI;

pub extern "c" fn gai_strerror(errcode: EAI) [*:0]const u8;

pub extern "c" fn poll(fds: [*]pollfd, nfds: nfds_t, timeout: c_int) c_int;
pub extern "c" fn ppoll(fds: [*]pollfd, nfds: nfds_t, timeout: ?*const timespec, sigmask: ?*const sigset_t) c_int;

pub extern "c" fn dn_expand(
    msg: [*:0]const u8,
    eomorig: [*:0]const u8,
    comp_dn: [*:0]const u8,
    exp_dn: [*:0]u8,
    length: c_int,
) c_int;

pub const PTHREAD_MUTEX_INITIALIZER = pthread_mutex_t{};
pub extern "c" fn pthread_mutex_lock(mutex: *pthread_mutex_t) E;
pub extern "c" fn pthread_mutex_unlock(mutex: *pthread_mutex_t) E;
pub extern "c" fn pthread_mutex_trylock(mutex: *pthread_mutex_t) E;
pub extern "c" fn pthread_mutex_destroy(mutex: *pthread_mutex_t) E;

pub const PTHREAD_COND_INITIALIZER = pthread_cond_t{};
pub extern "c" fn pthread_cond_wait(noalias cond: *pthread_cond_t, noalias mutex: *pthread_mutex_t) E;
pub extern "c" fn pthread_cond_timedwait(noalias cond: *pthread_cond_t, noalias mutex: *pthread_mutex_t, noalias abstime: *const timespec) E;
pub extern "c" fn pthread_cond_signal(cond: *pthread_cond_t) E;
pub extern "c" fn pthread_cond_broadcast(cond: *pthread_cond_t) E;
pub extern "c" fn pthread_cond_destroy(cond: *pthread_cond_t) E;

pub extern "c" fn pthread_rwlock_destroy(rwl: *pthread_rwlock_t) callconv(.C) E;
pub extern "c" fn pthread_rwlock_rdlock(rwl: *pthread_rwlock_t) callconv(.C) E;
pub extern "c" fn pthread_rwlock_wrlock(rwl: *pthread_rwlock_t) callconv(.C) E;
pub extern "c" fn pthread_rwlock_tryrdlock(rwl: *pthread_rwlock_t) callconv(.C) E;
pub extern "c" fn pthread_rwlock_trywrlock(rwl: *pthread_rwlock_t) callconv(.C) E;
pub extern "c" fn pthread_rwlock_unlock(rwl: *pthread_rwlock_t) callconv(.C) E;

pub const pthread_t = *opaque {};
pub const FILE = opaque {};

pub extern "c" fn dlopen(path: ?[*:0]const u8, mode: RTLD) ?*anyopaque;
pub extern "c" fn dlclose(handle: *anyopaque) c_int;
pub extern "c" fn dlsym(handle: ?*anyopaque, symbol: [*:0]const u8) ?*anyopaque;
pub extern "c" fn dlerror() ?[*:0]u8;

pub extern "c" fn sync() void;
pub extern "c" fn syncfs(fd: c_int) c_int;
pub extern "c" fn fsync(fd: c_int) c_int;
pub extern "c" fn fdatasync(fd: c_int) c_int;

pub extern "c" fn prctl(option: c_int, ...) c_int;

pub extern "c" fn getrlimit(resource: rlimit_resource, rlim: *rlimit) c_int;
pub extern "c" fn setrlimit(resource: rlimit_resource, rlim: *const rlimit) c_int;

pub extern "c" fn fmemopen(noalias buf: ?*anyopaque, size: usize, noalias mode: [*:0]const u8) ?*FILE;

pub extern "c" fn syslog(priority: c_int, message: [*:0]const u8, ...) void;
pub extern "c" fn openlog(ident: [*:0]const u8, logopt: c_int, facility: c_int) void;
pub extern "c" fn closelog() void;
pub extern "c" fn setlogmask(maskpri: c_int) c_int;

pub extern "c" fn if_nametoindex([*:0]const u8) c_int;

pub extern "c" fn getpid() pid_t;
pub extern "c" fn getppid() pid_t;

/// These are implementation defined but share identical values in at least musl and glibc:
/// - https://git.musl-libc.org/cgit/musl/tree/include/locale.h?id=ab31e9d6a0fa7c5c408856c89df2dfb12c344039#n18
/// - https://sourceware.org/git/?p=glibc.git;a=blob;f=locale/bits/locale.h;h=0fcbb66114be5fef0577dc9047256eb508c45919;hb=c90cfce849d010474e8cccf3e5bff49a2c8b141f#l26
pub const LC = enum(c_int) {
    CTYPE = 0,
    NUMERIC = 1,
    TIME = 2,
    COLLATE = 3,
    MONETARY = 4,
    MESSAGES = 5,
    ALL = 6,
    PAPER = 7,
    NAME = 8,
    ADDRESS = 9,
    TELEPHONE = 10,
    MEASUREMENT = 11,
    IDENTIFICATION = 12,
    _,
};

pub extern "c" fn setlocale(category: LC, locale: ?[*:0]const u8) ?[*:0]const u8;

pub const getcontext = if (builtin.target.isAndroid() or builtin.target.os.tag == .openbsd)
{} // android bionic and openbsd libc does not implement getcontext
else if (native_os == .linux and builtin.target.isMusl())
    linux.getcontext
else
    private.getcontext;

pub const max_align_t = if (native_abi == .msvc or native_abi == .itanium)
    f64
else if (builtin.target.isDarwin())
    c_longdouble
else
    extern struct {
        a: c_longlong,
        b: c_longdouble,
    };

pub extern "c" fn pthread_getthreadid_np() c_int;
pub extern "c" fn pthread_set_name_np(thread: pthread_t, name: [*:0]const u8) void;
pub extern "c" fn pthread_get_name_np(thread: pthread_t, name: [*:0]u8, len: usize) void;

// OS-specific bits. These are protected from being used on the wrong OS by
// comptime assertions inside each OS-specific file.

pub const AF_SUN = solaris.AF_SUN;
pub const AT_SUN = solaris.AT_SUN;
pub const FILE_EVENT = solaris.FILE_EVENT;
pub const GETCONTEXT = solaris.GETCONTEXT;
pub const GETUSTACK = solaris.GETUSTACK;
pub const PORT_ALERT = solaris.PORT_ALERT;
pub const PORT_SOURCE = solaris.PORT_SOURCE;
pub const POSIX_FADV = solaris.POSIX_FADV;
pub const SCM = solaris.SCM;
pub const SETCONTEXT = solaris.SETCONTEXT;
pub const SETUSTACK = solaris.GETUSTACK;
pub const SFD = solaris.SFD;
pub const _SC = solaris._SC;
pub const cmsghdr = solaris.cmsghdr;
pub const ctid_t = solaris.ctid_t;
pub const file_obj = solaris.file_obj;
pub const fpregset_t = solaris.fpregset_t;
pub const id_t = solaris.id_t;
pub const lif_ifinfo_req = solaris.lif_ifinfo_req;
pub const lif_nd_req = solaris.lif_nd_req;
pub const lifreq = solaris.lifreq;
pub const major_t = solaris.major_t;
pub const minor_t = solaris.minor_t;
pub const poolid_t = solaris.poolid_t;
pub const port_notify = solaris.port_notify;
pub const priority = solaris.priority;
pub const procfs = solaris.procfs;
pub const projid_t = solaris.projid_t;
pub const signalfd_siginfo = solaris.signalfd_siginfo;
pub const sysconf = solaris.sysconf;
pub const taskid_t = solaris.taskid_t;
pub const zoneid_t = solaris.zoneid_t;

pub const DirEnt = haiku.DirEnt;
pub const _get_next_area_info = haiku._get_next_area_info;
pub const _get_next_image_info = haiku._get_next_image_info;
pub const _get_team_info = haiku._get_team_info;
pub const _kern_get_current_team = haiku._kern_get_current_team;
pub const _kern_open_dir = haiku._kern_open_dir;
pub const _kern_read_dir = haiku._kern_read_dir;
pub const _kern_read_stat = haiku._kern_read_stat;
pub const _kern_rewind_dir = haiku._kern_rewind_dir;
pub const area_id = haiku.area_id;
pub const area_info = haiku.area_info;
pub const directory_which = haiku.directory_which;
pub const find_directory = haiku.find_directory;
pub const find_thread = haiku.find_thread;
pub const get_system_info = haiku.get_system_info;
pub const image_info = haiku.image_info;
pub const port_id = haiku.port_id;
pub const sem_id = haiku.sem_id;
pub const status_t = haiku.status_t;
pub const system_info = haiku.system_info;
pub const team_id = haiku.team_id;
pub const team_info = haiku.team_info;
pub const thread_id = haiku.thread_id;
pub const vregs = haiku.vregs;

pub const AUTH = openbsd.AUTH;
pub const BI = openbsd.BI;
pub const FUTEX = openbsd.FUTEX;
pub const HW = openbsd.HW;
pub const PTHREAD_STACK_MIN = openbsd.PTHREAD_STACK_MIN;
pub const TCFLUSH = openbsd.TCFLUSH;
pub const TCIO = openbsd.TCIO;
pub const auth_approval = openbsd.auth_approval;
pub const auth_call = openbsd.auth_call;
pub const auth_cat = openbsd.auth_cat;
pub const auth_challenge = openbsd.auth_challenge;
pub const auth_check_change = openbsd.auth_check_change;
pub const auth_check_expire = openbsd.auth_check_expire;
pub const auth_checknologin = openbsd.auth_checknologin;
pub const auth_clean = openbsd.auth_clean;
pub const auth_close = openbsd.auth_close;
pub const auth_clrenv = openbsd.auth_clrenv;
pub const auth_clroption = openbsd.auth_clroption;
pub const auth_clroptions = openbsd.auth_clroptions;
pub const auth_getitem = openbsd.auth_getitem;
pub const auth_getpwd = openbsd.auth_getpwd;
pub const auth_getstate = openbsd.auth_getstate;
pub const auth_getvalue = openbsd.auth_getvalue;
pub const auth_item_t = openbsd.auth_item_t;
pub const auth_mkvalue = openbsd.auth_mkvalue;
pub const auth_open = openbsd.auth_open;
pub const auth_session_t = openbsd.auth_session_t;
pub const auth_setdata = openbsd.auth_setdata;
pub const auth_setenv = openbsd.auth_setenv;
pub const auth_setitem = openbsd.auth_setitem;
pub const auth_setoption = openbsd.auth_setoption;
pub const auth_setpwd = openbsd.auth_setpwd;
pub const auth_setstate = openbsd.auth_setstate;
pub const auth_userchallenge = openbsd.auth_userchallenge;
pub const auth_usercheck = openbsd.auth_usercheck;
pub const auth_userokay = openbsd.auth_userokay;
pub const auth_userresponse = openbsd.auth_userresponse;
pub const auth_verify = openbsd.auth_verify;
pub const bcrypt = openbsd.bcrypt;
pub const bcrypt_checkpass = openbsd.bcrypt_checkpass;
pub const bcrypt_gensalt = openbsd.bcrypt_gensalt;
pub const bcrypt_newhash = openbsd.bcrypt_newhash;
pub const endpwent = openbsd.endpwent;
pub const futex = openbsd.futex;
pub const getpwent = openbsd.getpwent;
pub const getpwnam_r = openbsd.getpwnam_r;
pub const getpwnam_shadow = openbsd.getpwnam_shadow;
pub const getpwuid_r = openbsd.getpwuid_r;
pub const getpwuid_shadow = openbsd.getpwuid_shadow;
pub const getthrid = openbsd.getthrid;
pub const login_cap_t = openbsd.login_cap_t;
pub const login_close = openbsd.login_close;
pub const login_getcapbool = openbsd.login_getcapbool;
pub const login_getcapnum = openbsd.login_getcapnum;
pub const login_getcapsize = openbsd.login_getcapsize;
pub const login_getcapstr = openbsd.login_getcapstr;
pub const login_getcaptime = openbsd.login_getcaptime;
pub const login_getclass = openbsd.login_getclass;
pub const login_getstyle = openbsd.login_getstyle;
pub const pledge = openbsd.pledge;
pub const pthread_spinlock_t = openbsd.pthread_spinlock_t;
pub const pw_dup = openbsd.pw_dup;
pub const setclasscontext = openbsd.setclasscontext;
pub const setpassent = openbsd.setpassent;
pub const setpwent = openbsd.setpwent;
pub const setusercontext = openbsd.setusercontext;
pub const uid_from_user = openbsd.uid_from_user;
pub const unveil = openbsd.unveil;
pub const user_from_uid = openbsd.user_from_uid;

pub const CAP_RIGHTS_VERSION = freebsd.CAP_RIGHTS_VERSION;
pub const KINFO_FILE_SIZE = freebsd.KINFO_FILE_SIZE;
pub const MFD = freebsd.MFD;
pub const UMTX_ABSTIME = freebsd.UMTX_ABSTIME;
pub const UMTX_OP = freebsd.UMTX_OP;
pub const _umtx_op = freebsd._umtx_op;
pub const _umtx_time = freebsd._umtx_time;
pub const cap_rights = freebsd.cap_rights;
pub const fflags_t = freebsd.fflags_t;
pub const fsblkcnt_t = freebsd.fsblkcnt_t;
pub const fsfilcnt_t = freebsd.fsfilcnt_t;
pub const kinfo_file = freebsd.kinfo_file;
pub const kinfo_getfile = freebsd.kinfo_getfile;

pub const COPYFILE = darwin.COPYFILE;
pub const CPUFAMILY = darwin.CPUFAMILY;
pub const DB_RECORDTYPE = darwin.DB_RECORDTYPE;
pub const EXC = darwin.EXC;
pub const EXCEPTION = darwin.EXCEPTION;
pub const MACH_MSG_TYPE = darwin.MACH_MSG_TYPE;
pub const MACH_PORT_RIGHT = darwin.MACH_PORT_RIGHT;
pub const MACH_TASK_BASIC_INFO = darwin.MACH_TASK_BASIC_INFO;
pub const MACH_TASK_BASIC_INFO_COUNT = darwin.MACH_TASK_BASIC_INFO_COUNT;
pub const MATTR = darwin.MATTR;
pub const NSVersionOfRunTimeLibrary = darwin.NSVersionOfRunTimeLibrary;
pub const OPEN_MAX = darwin.OPEN_MAX;
pub const POSIX_SPAWN = darwin.POSIX_SPAWN;
pub const TASK_NULL = darwin.TASK_NULL;
pub const TASK_VM_INFO = darwin.TASK_VM_INFO;
pub const TASK_VM_INFO_COUNT = darwin.TASK_VM_INFO_COUNT;
pub const THREAD_BASIC_INFO = darwin.THREAD_BASIC_INFO;
pub const THREAD_BASIC_INFO_COUNT = darwin.THREAD_BASIC_INFO_COUNT;
pub const THREAD_IDENTIFIER_INFO_COUNT = darwin.THREAD_IDENTIFIER_INFO_COUNT;
pub const THREAD_NULL = darwin.THREAD_NULL;
pub const THREAD_STATE_NONE = darwin.THREAD_STATE_NONE;
pub const UL = darwin.UL;
pub const VM = darwin.VM;
pub const _NSGetExecutablePath = darwin._NSGetExecutablePath;
pub const __getdirentries64 = darwin.__getdirentries64;
pub const __ulock_wait = darwin.__ulock_wait;
pub const __ulock_wait2 = darwin.__ulock_wait2;
pub const __ulock_wake = darwin.__ulock_wake;
pub const _dyld_get_image_header = darwin._dyld_get_image_header;
pub const _dyld_get_image_name = darwin._dyld_get_image_name;
pub const _dyld_get_image_vmaddr_slide = darwin._dyld_get_image_vmaddr_slide;
pub const _dyld_image_count = darwin._dyld_image_count;
pub const _host_page_size = darwin._host_page_size;
pub const clock_get_time = darwin.clock_get_time;
pub const dispatch_release = darwin.dispatch_release;
pub const dispatch_semaphore_create = darwin.dispatch_semaphore_create;
pub const dispatch_semaphore_signal = darwin.dispatch_semaphore_signal;
pub const dispatch_semaphore_wait = darwin.dispatch_semaphore_wait;
pub const dispatch_time = darwin.dispatch_time;
pub const fcopyfile = darwin.fcopyfile;
pub const kern_return_t = darwin.kern_return_t;
pub const kevent64 = darwin.kevent64;
pub const mach_absolute_time = darwin.mach_absolute_time;
pub const mach_continuous_time = darwin.mach_continuous_time;
pub const mach_hdr = darwin.mach_hdr;
pub const mach_host_self = darwin.mach_host_self;
pub const mach_msg = darwin.mach_msg;
pub const mach_msg_type_number_t = darwin.mach_msg_type_number_t;
pub const mach_port_allocate = darwin.mach_port_allocate;
pub const mach_port_array_t = darwin.mach_port_array_t;
pub const mach_port_deallocate = darwin.mach_port_deallocate;
pub const mach_port_insert_right = darwin.mach_port_insert_right;
pub const mach_port_name_t = darwin.mach_port_name_t;
pub const mach_port_t = darwin.mach_port_t;
pub const mach_task_basic_info = darwin.mach_task_basic_info;
pub const mach_task_self = darwin.mach_task_self;
pub const mach_timebase_info = darwin.mach_timebase_info;
pub const mach_vm_protect = darwin.mach_vm_protect;
pub const mach_vm_read = darwin.mach_vm_read;
pub const mach_vm_region = darwin.mach_vm_region;
pub const mach_vm_region_recurse = darwin.mach_vm_region_recurse;
pub const mach_vm_write = darwin.mach_vm_write;
pub const os_log_create = darwin.os_log_create;
pub const os_log_type_enabled = darwin.os_log_type_enabled;
pub const os_signpost_enabled = darwin.os_signpost_enabled;
pub const os_signpost_id_generate = darwin.os_signpost_id_generate;
pub const os_signpost_id_make_with_pointer = darwin.os_signpost_id_make_with_pointer;
pub const os_signpost_interval_begin = darwin.os_signpost_interval_begin;
pub const os_signpost_interval_end = darwin.os_signpost_interval_end;
pub const os_unfair_lock = darwin.os_unfair_lock;
pub const os_unfair_lock_assert_not_owner = darwin.os_unfair_lock_assert_not_owner;
pub const os_unfair_lock_assert_owner = darwin.os_unfair_lock_assert_owner;
pub const os_unfair_lock_lock = darwin.os_unfair_lock_lock;
pub const os_unfair_lock_trylock = darwin.os_unfair_lock_trylock;
pub const os_unfair_lock_unlock = darwin.os_unfair_lock_unlock;
pub const pid_for_task = darwin.pid_for_task;
pub const posix_spawn = darwin.posix_spawn;
pub const posix_spawn_file_actions_addchdir_np = darwin.posix_spawn_file_actions_addchdir_np;
pub const posix_spawn_file_actions_addclose = darwin.posix_spawn_file_actions_addclose;
pub const posix_spawn_file_actions_adddup2 = darwin.posix_spawn_file_actions_adddup2;
pub const posix_spawn_file_actions_addfchdir_np = darwin.posix_spawn_file_actions_addfchdir_np;
pub const posix_spawn_file_actions_addinherit_np = darwin.posix_spawn_file_actions_addinherit_np;
pub const posix_spawn_file_actions_addopen = darwin.posix_spawn_file_actions_addopen;
pub const posix_spawn_file_actions_destroy = darwin.posix_spawn_file_actions_destroy;
pub const posix_spawn_file_actions_init = darwin.posix_spawn_file_actions_init;
pub const posix_spawn_file_actions_t = darwin.posix_spawn_file_actions_t;
pub const posix_spawnattr_destroy = darwin.posix_spawnattr_destroy;
pub const posix_spawnattr_getflags = darwin.posix_spawnattr_getflags;
pub const posix_spawnattr_init = darwin.posix_spawnattr_init;
pub const posix_spawnattr_setflags = darwin.posix_spawnattr_setflags;
pub const posix_spawnattr_t = darwin.posix_spawnattr_t;
pub const posix_spawnp = darwin.posix_spawnp;
pub const pthread_attr_get_qos_class_np = darwin.pthread_attr_get_qos_class_np;
pub const pthread_attr_set_qos_class_np = darwin.pthread_attr_set_qos_class_np;
pub const pthread_get_qos_class_np = darwin.pthread_get_qos_class_np;
pub const pthread_set_qos_class_self_np = darwin.pthread_set_qos_class_self_np;
pub const ptrace = darwin.ptrace;
pub const sigaddset = darwin.sigaddset;
pub const task_for_pid = darwin.task_for_pid;
pub const task_get_exception_ports = darwin.task_get_exception_ports;
pub const task_info = darwin.task_info;
pub const task_info_t = darwin.task_info_t;
pub const task_resume = darwin.task_resume;
pub const task_set_exception_ports = darwin.task_set_exception_ports;
pub const task_suspend = darwin.task_suspend;
pub const task_threads = darwin.task_threads;
pub const task_vm_info_data_t = darwin.task_vm_info_data_t;
pub const thread_basic_info = darwin.thread_basic_info;
pub const thread_get_state = darwin.thread_get_state;
pub const thread_identifier_info = darwin.thread_identifier_info;
pub const thread_info = darwin.thread_info;
pub const thread_info_t = darwin.thread_info_t;
pub const thread_resume = darwin.thread_resume;
pub const thread_set_state = darwin.thread_set_state;
pub const vm_deallocate = darwin.vm_deallocate;
pub const vm_machine_attribute = darwin.vm_machine_attribute;
pub const vm_machine_attribute_val_t = darwin.vm_machine_attribute_val_t;
pub const vm_offset_t = darwin.vm_offset_t;
pub const vm_prot_t = darwin.vm_prot_t;
pub const vm_region_basic_info_64 = darwin.vm_region_basic_info_64;
pub const vm_region_extended_info = darwin.vm_region_extended_info;
pub const vm_region_info_t = darwin.vm_region_info_t;
pub const vm_region_recurse_info_t = darwin.vm_region_recurse_info_t;
pub const vm_region_submap_info_64 = darwin.vm_region_submap_info_64;
pub const vm_region_submap_short_info_64 = darwin.vm_region_submap_short_info_64;
pub const vm_region_top_info = darwin.vm_region_top_info;

pub const _ksiginfo = netbsd._ksiginfo;
pub const _lwp_self = netbsd._lwp_self;
pub const lwpid_t = netbsd.lwpid_t;

pub const lwp_gettid = dragonfly.lwp_gettid;
pub const umtx_sleep = dragonfly.umtx_sleep;
pub const umtx_wakeup = dragonfly.umtx_wakeup;

/// External definitions shared by two or more operating systems.
const private = struct {
    extern "c" fn close(fd: fd_t) c_int;
    extern "c" fn clock_getres(clk_id: clockid_t, tp: *timespec) c_int;
    extern "c" fn clock_gettime(clk_id: clockid_t, tp: *timespec) c_int;
    extern "c" fn copy_file_range(fd_in: fd_t, off_in: ?*i64, fd_out: fd_t, off_out: ?*i64, len: usize, flags: c_uint) isize;
    extern "c" fn flock(fd: fd_t, operation: c_int) c_int;
    extern "c" fn fork() c_int;
    extern "c" fn fstat(fd: fd_t, buf: *Stat) c_int;
    extern "c" fn fstatat(dirfd: fd_t, path: [*:0]const u8, buf: *Stat, flag: u32) c_int;
    extern "c" fn getdirentries(fd: fd_t, buf_ptr: [*]u8, nbytes: usize, basep: *i64) isize;
    extern "c" fn getdents(fd: c_int, buf_ptr: [*]u8, nbytes: usize) switch (native_os) {
        .freebsd => isize,
        .solaris, .illumos => usize,
        else => c_int,
    };
    extern "c" fn getrusage(who: c_int, usage: *rusage) c_int;
    extern "c" fn gettimeofday(noalias tv: ?*timeval, noalias tz: ?*timezone) c_int;
    extern "c" fn msync(addr: *align(page_size) const anyopaque, len: usize, flags: c_int) c_int;
    extern "c" fn nanosleep(rqtp: *const timespec, rmtp: ?*timespec) c_int;
    extern "c" fn pipe2(fds: *[2]fd_t, flags: O) c_int;
    extern "c" fn readdir(dir: *DIR) ?*dirent;
    extern "c" fn realpath(noalias file_name: [*:0]const u8, noalias resolved_name: [*]u8) ?[*:0]u8;
    extern "c" fn sched_yield() c_int;
    extern "c" fn sendfile(out_fd: fd_t, in_fd: fd_t, offset: ?*off_t, count: usize) isize;
    extern "c" fn sigaction(sig: c_int, noalias act: ?*const Sigaction, noalias oact: ?*Sigaction) c_int;
    extern "c" fn sigfillset(set: ?*sigset_t) void;
    extern "c" fn sigprocmask(how: c_int, noalias set: ?*const sigset_t, noalias oset: ?*sigset_t) c_int;
    extern "c" fn socket(domain: c_uint, sock_type: c_uint, protocol: c_uint) c_int;
    extern "c" fn stat(noalias path: [*:0]const u8, noalias buf: *Stat) c_int;
    extern "c" fn sigaltstack(ss: ?*stack_t, old_ss: ?*stack_t) c_int;

    extern "c" fn pthread_setname_np(thread: pthread_t, name: [*:0]const u8) c_int;
    extern "c" fn getcontext(ucp: *ucontext_t) c_int;

    extern "c" fn getrandom(buf_ptr: [*]u8, buf_len: usize, flags: c_uint) isize;
    extern "c" fn getentropy(buffer: [*]u8, size: usize) c_int;
    extern "c" fn arc4random_buf(buf: [*]u8, len: usize) void;

    extern "c" fn _msize(memblock: ?*anyopaque) usize;
    extern "c" fn malloc_size(?*const anyopaque) usize;
    extern "c" fn malloc_usable_size(?*const anyopaque) usize;
    extern "c" fn posix_memalign(memptr: *?*anyopaque, alignment: usize, size: usize) c_int;

    /// macos modernized symbols.
    /// x86_64 links to $INODE64 suffix for 64-bit support.
    /// Note these are not necessary on aarch64.
    extern "c" fn @"fstat$INODE64"(fd: fd_t, buf: *Stat) c_int;
    extern "c" fn @"fstatat$INODE64"(dirfd: fd_t, path: [*:0]const u8, buf: *Stat, flag: u32) c_int;
    extern "c" fn @"readdir$INODE64"(dir: *DIR) ?*dirent;
    extern "c" fn @"stat$INODE64"(noalias path: [*:0]const u8, noalias buf: *Stat) c_int;

    /// macos modernized symbols.
    extern "c" fn @"realpath$DARWIN_EXTSN"(noalias file_name: [*:0]const u8, noalias resolved_name: [*]u8) ?[*:0]u8;
    extern "c" fn __getdirentries64(fd: fd_t, buf_ptr: [*]u8, buf_len: usize, basep: *i64) isize;

    extern "c" fn pthread_threadid_np(thread: ?pthread_t, thread_id: *u64) c_int;

    /// netbsd modernized symbols.
    extern "c" fn __clock_getres50(clk_id: clockid_t, tp: *timespec) c_int;
    extern "c" fn __clock_gettime50(clk_id: clockid_t, tp: *timespec) c_int;
    extern "c" fn __fstat50(fd: fd_t, buf: *Stat) c_int;
    extern "c" fn __getrusage50(who: c_int, usage: *rusage) c_int;
    extern "c" fn __gettimeofday50(noalias tv: ?*timeval, noalias tz: ?*timezone) c_int;
    extern "c" fn __libc_thr_yield() c_int;
    extern "c" fn __msync13(addr: *align(std.mem.page_size) const anyopaque, len: usize, flags: c_int) c_int;
    extern "c" fn __nanosleep50(rqtp: *const timespec, rmtp: ?*timespec) c_int;
    extern "c" fn __sigaction14(sig: c_int, noalias act: ?*const Sigaction, noalias oact: ?*Sigaction) c_int;
    extern "c" fn __sigfillset14(set: ?*sigset_t) void;
    extern "c" fn __sigprocmask14(how: c_int, noalias set: ?*const sigset_t, noalias oset: ?*sigset_t) c_int;
    extern "c" fn __socket30(domain: c_uint, sock_type: c_uint, protocol: c_uint) c_int;
    extern "c" fn __stat50(path: [*:0]const u8, buf: *Stat) c_int;
    extern "c" fn __getdents30(fd: c_int, buf_ptr: [*]u8, nbytes: usize) c_int;
    extern "c" fn __sigaltstack14(ss: ?*stack_t, old_ss: ?*stack_t) c_int;

    // Don't forget to add another clown when an OS picks yet another unique
    // symbol name for errno location!
    // 🤡🤡🤡🤡🤡🤡

    extern "c" fn ___errno() *c_int;
    extern "c" fn __errno() *c_int;
    extern "c" fn __errno_location() *c_int;
    extern "c" fn __error() *c_int;
    extern "c" fn _errno() *c_int;

    extern threadlocal var errno: c_int;

    fn errnoFromThreadLocal() *c_int {
        return &errno;
    }
};