diff --git a/Documentation/watchdog/src/watchdog-simple.c b/Documentation/watchdog/src/watchdog-simple.c
index 85cf17c48669..47801bc7e742 100644
--- a/Documentation/watchdog/src/watchdog-simple.c
+++ b/Documentation/watchdog/src/watchdog-simple.c
@@ -1,4 +1,6 @@
+#include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
 #include <fcntl.h>
 
 int main(int argc, const char *argv[]) {