разблокировать семафор (unlock a semaphore)
Имя (Name)
sem_post - unlock a semaphore
Синопсис (Synopsis)
#include <semaphore.h>
int sem_post(sem_t *sem);
Link with -pthread.
Описание (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.
Возвращаемое значение (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.
Ошибки (Error)
EINVAL sem is not a valid semaphore.
EOVERFLOW
The maximum allowable value for a semaphore would be
exceeded.
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│sem_post() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘
Стандарты (Conforming to)
POSIX.1-2001.
Примечание (Note)
sem_post() is async-signal-safe: it may be safely called within a
signal handler.
Примеры (Examples)
See sem_wait(3) and shm_open(3).
Смотри также (See also)
sem_getvalue(3), sem_wait(3), sem_overview(7), signal-safety(7)
