centos man page for sem_post

SEM_POST(3)						     Linux Programmer's Manual						       SEM_POST(3)

NAME
       sem_post - unlock a semaphore

SYNOPSIS
       #include <semaphore.h>

       int sem_post(sem_t *sem);

       Link with -pthread.

DESCRIPTION
       sem_post()  increments  (unlocks)  the  semaphore pointed to by sem.  If the semaphore's value consequently becomes greater than zero, then
       another process or thread blocked in a sem_wait(3) call will be woken up and proceed to lock the semaphore.

RETURN VALUE
       sem_post() returns 0 on success; on error, the value of the semaphore is left unchanged, -1 is returned, and errno is set to  indicate  the
       error.

ERRORS
       EINVAL sem is not a valid semaphore.

       EOVERFLOW
	      The maximum allowable value for a semaphore would be exceeded.

CONFORMING TO
       POSIX.1-2001.

NOTES
       sem_post() is async-signal-safe: it may be safely called within a signal handler.

EXAMPLE
       See sem_wait(3).

SEE ALSO
       sem_getvalue(3), sem_wait(3), sem_overview(7)

COLOPHON
       This  page is part of release 3.53 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2012-05-13							       SEM_POST(3)