netbsd man page for sem_init

SEM_INIT(3)						   BSD 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, which this implementation is not capable of.

     Following a successful call to sem_init(), sem can be used as an argument in subsequent calls to sem_wait, 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  sem is no longer valid after a successful call to sem_destroy.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 indi-
     cate the error.

ERRORS
     sem_init() will fail if:

     [EINVAL]		value exceeds SEM_VALUE_MAX.

     [ENOSPC]		Memory allocation error.

     [EPERM]		Unable to initialize a shared semaphore.

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

STANDARDS
     sem_init() conforms to ISO/IEC 9945-1:1996 (``POSIX.1'').

     This implementation does not support shared semaphores, and reports this fact by setting errno to EPERM.  This is perhaps a stretch of the
     intention of POSIX, but is compliant, with the caveat that sem_init() always reports a permissions error when an attempt to create a shared
     semaphore is made.

BSD
								 January 22, 2003							       BSD