mainlining shenanigans
e4d7b113fd
A common mistake is to assume that initializing a var with:
struct foo f = { 0 };
Would initialize a zeroed struct. Actually, what this does is
to initialize the first element of the struct to zero.
According to C99 Standard 6.7.8.21:
"If there are fewer initializers in a brace-enclosed
list than there are elements or members of an aggregate,
or fewer characters in a string literal used to initialize
an array of known size than there are elements in the array,
the remainder of the aggregate shall be initialized implicitly
the same as objects that have static storage duration."
So, in practice, it could zero the entire struct, but, if the
first element is not an integer, it will produce warnings:
drivers/staging/media/sunxi/cedrus/cedrus.c:drivers/staging/media/sunxi/cedrus/cedrus.c:78:49: warning: Using plain integer as NULL pointer
drivers/staging/media/sunxi/cedrus/cedrus_dec.c:drivers/staging/media/sunxi/cedrus/cedrus_dec.c:29:35: warning: Using plain integer as NULL pointer
As the right initialization would be, instead:
struct foo f = { NULL };
Another way to initialize it with gcc is to use:
struct foo f = {};
That seems to be a gcc extension, but clang also does the right thing,
and that's a clean way for doing it.
Anyway, I decided to check upstream what's the most commonly pattern.
The "= {}" pattern has about 2000 entries:
$ git grep -E "=\s*\{\s*\}"|wc -l
1951
The standard-C compliant pattern has about 2500 entries:
$ git grep -E "=\s*\{\s*NULL\s*\}"|wc -l
137
$ git grep -E "=\s*\{\s*0\s*\}"|wc -l
2323
Meaning that developers have split options on that.
So, let's opt to the simpler form.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
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Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.