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Command: sem_init | Section: 3 | Source: NetBSD | File: sem_init.3
SEM_INIT(3) FreeBSD Library Functions Manual SEM_INIT(3)
NAME
sem_init - initialize an unnamed semaphore
LIBRARY
POSIX Real-time Library (librt, -lrt)
SYNOPSIS
#include <semaphore.h>
int
sem_init(sem_t *sem, int pshared, unsigned int value);
DESCRIPTION
The sem_init() function initializes the unnamed semaphore pointed to by
sem to have the value value. A non-zero value for pshared specifies a
shared semaphore that can be used by multiple processes.
Following a successful call to sem_init(), sem can be used as an argument
in subsequent calls to sem_wait(), sem_timedwait(), sem_trywait(),
sem_post(), and sem_destroy(). sem is no longer valid after a successful
call to sem_destroy.
RETURN VALUES
The sem_init() function returns the value 0 if successful; otherwise the
value -1 is returned and the global variable errno is set to indicate the
error.
ERRORS
sem_init() will fail if:
[EINVAL] value exceeds SEM_VALUE_MAX.
[ENOSPC] There was memory allocation error, or the limit on
available semaphores (SEM_NSEMS_MAX) has been
exceeded.
[EPERM] Unable to initialize a shared semaphore.
SEE ALSO
sem_destroy(3), sem_post(3), sem_timedwait(3), sem_trywait(3),
sem_wait(3)
STANDARDS
sem_init() conforms to ISO/IEC 9945-1:1996 ("POSIX.1").
FreeBSD 14.1-RELEASE-p8 February 21, 2019 FreeBSD 14.1-RELEASE-p8