sem_post(3C)

NAME
     sem_post - release a posix named or unnamed semaphore

SYNOPSIS
     #include <semaphore.h>
     int sem_post(sem_t *sem);

DESCRIPTION
     sem_post atomically increments the value of the semaphore located at
     address sem.  If any processes are blocked on the semaphore, the highest
     priority process waiting the longest is unblocked and made runnable.

     The address sem may reside anywhere in the calling processes address
     space, but the process must have read and write access to sem.

     sem_post will fail if the following is true:

     [EINVAL]    The semaphore located at address sem is not a valid posix
                 named or unnamed semaphore.

SEE ALSO
     sem_init(3C), sem_destroy(3C), sem_getvalue(3C), sem_post(3C),
     sem_wait(3C), sem_trywait(3C), sem_open(3C), sem_close(3C),
     sem_unlink(3C),

DIAGNOSTICS
     Upon successful completion, a value of 0 is returned to the calling
     process. Otherwise, a value of -1 is returned and errno is set to
     indicate the error.