SEM_POST(3) | Library Functions Manual | SEM_POST(3) |
sem_post
—
#include <semaphore.h>
int
sem_post
(sem_t
*sem);
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
() or
sem_timedwait
().
sem_post
() is signal-reentrant and may be
called within signal handlers.
sem_post
() function returns the value 0 if
successful; otherwise the value -1 is returned and the global variable
errno is set to indicate the error.
sem_post
() will fail if:
EINVAL
]sem_post
() conforms to ISO/IEC
9945-1:1996 (“POSIX.1”).
February 29, 2012 | NetBSD 9.0 |