sem_post(2) [osx man page]

SEM_POST(2)						      BSD System Calls Manual						       SEM_POST(2)

NAME

     sem_post -- unlock a semaphore

SYNOPSIS

     #include <semaphore.h>

     int
     sem_post(sem_t *sem);

DESCRIPTION

     The semaphore referenced by sem is unlocked, the value of the semaphore is incremented, and all threads which are waiting on the semaphore
     are awakened.

     sem_post() is reentrant with respect to signals and may be called from within a signal hanlder.

     If successful, sem_post() will return 0.  Otherwise, -1 is returned and errno is set.

ERRORS

     sem_post() succeeds unless:

     [EINVAL]		sem is not a valid semaphore descriptor.

SEE ALSO

     sem_open(2), sem_trywait(2), sem_wait(2), semctl(2), semget(2), semop(2)

HISTORY

     sem_post() is specified in the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995).

Darwin								   June 8, 2000 							    Darwin

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 -lrt or -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 3.27 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								    2009-03-30							       SEM_POST(3)