SEM_INIT(3)            FreeBSD Library Functions Manual            SEM_INIT(3)

NAME
     sem_init - initialize an unnamed semaphore

LIBRARY
     Standard C Library (libc, -lc)

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, the semaphore should be located in shared
     memory region (see mmap(2), shm_open(2), and shmget(2)), any process
     having read and write access to address sem can perform semaphore
     operations on sem.

     Following a successful call to sem_init(), sem can be used as an argument
     in subsequent calls to sem_wait(3), sem_trywait(3), sem_post(3), and
     sem_destroy(3).  The sem argument is no longer valid after a successful
     call to sem_destroy(3).

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
     The sem_init() function will fail if:

     [EINVAL]           The value argument exceeds SEM_VALUE_MAX.

     [ENOSPC]           Memory allocation error.

SEE ALSO
     sem_destroy(3), sem_getvalue(3), sem_post(3), sem_trywait(3), sem_wait(3)

STANDARDS
     The sem_init() function conforms to ISO/IEC 9945-1:1996 ("POSIX.1").

FreeBSD 13.1-RELEASE-p6         January 9, 2010        FreeBSD 13.1-RELEASE-p6