Name
sem_post — unlock a semaphore
Synopsis
#include <semaphore.h>
int
sem_post( |
sem_t * |
sem) ; |
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.
CONFORMING TO
POSIX.1-2001.
NOTES
sem_post
() is
async-signal-safe: it may be safely called within a signal
handler.
SEE ALSO
sem_getvalue(3), sem_wait(3), sem_overview(7)
t
Copyright (C) 2006 Michael Kerrisk <mtk-manpages@gmx.net>
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