semaphore.h(0p)

Usage

#include <semaphore.h>

Prolog

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

Overview

The <semaphore.h> header shall define the sem_t type, used in performing semaphore operations. The semaphore may be implemented using a file descriptor, in which case applications are able to open up at least a total of {OPEN_MAX} files and semaphores.

The <semaphore.h> header shall define the symbolic constant SEM_FAILED which shall have type sem_t *.

The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.

int    sem_close(sem_t *);
int    sem_destroy(sem_t *);
int    sem_getvalue(sem_t *restrict, int *restrict);
int    sem_init(sem_t *, int, unsigned);
sem_t *sem_open(const char *, int, ...);
int    sem_post(sem_t *);
int    sem_timedwait(sem_t *restrict, const struct timespec *restrict);
int    sem_trywait(sem_t *);
int    sem_unlink(const char *);
int    sem_wait(sem_t *);

Inclusion of the <semaphore.h> header may make visible symbols defined in the <fcntl.h> and <time.h> headers.

The following sections are informative.

Application usage

None.

Rationale

None.

Future directions

None.