netbsd man page for sem_post

SEM_POST(3)						   BSD Library Functions Manual 					       SEM_POST(3)

NAME
     sem_post -- increment (unlock) a semaphore

LIBRARY
     POSIX Real-time Library (librt, -lrt)

SYNOPSIS
     #include <semaphore.h>

     int
     sem_post(sem_t *sem);

DESCRIPTION
     The sem_post() function increments (unlocks) the semaphore pointed to by sem.  If there are threads blocked on the semaphore when sem_post()
     is called, then the highest priority thread that has been blocked the longest on the semaphore will be allowed to return from sem_wait().

     sem_post() is signal-reentrant and may be called within signal handlers.

RETURN VALUES
     The sem_post() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indi-
     cate the error.

ERRORS
     sem_post() will fail if:

     [EINVAL]		sem points to an invalid semaphore.

SEE ALSO
     sem_trywait(3), sem_wait(3)

STANDARDS
     sem_post() conforms to ISO/IEC 9945-1:1996 (``POSIX.1'').

BSD
								 January 22, 2003							       BSD