|| POSIX Programmer's Manual
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.
NAME sem_close - close a named semaphore (
int sem_close(sem_t *
sem_close() function shall indicate that the calling process is finished using the named semaphore indicated by
sem. The effects of calling
sem_close() for an unnamed semaphore (one created by
sem_init()) are undefined. The
sem_close() function shall deallocate (that is, make available for reuse by a subsequent
sem_open() by this process) any system resources allocated by the system for use by this process for this semaphore. The effect of subsequent use of the semaphore indicated by
sem by this process is undefined. If the semaphore has not been removed with a successful call to
sem_close() has no effect on the state of the semaphore. If the
sem_unlink() function has been successfully invoked for
name after the most recent call to
sem_open() with O_CREAT for this semaphore, then when all processes that have opened the semaphore close it, the semaphore is no longer accessible.
RETURN VALUE Upon successful completion, a value of zero shall be returned. Otherwise, a value of -1 shall be returned and
errno set to indicate the error.
() function shall fail if:
sem argument is not a valid semaphore descriptor.
The following sections are informative.
APPLICATION USAGE The
sem_close() function is part of the Semaphores option and need not be available on all implementations.
FUTURE DIRECTIONS None.
sem_unlink(), the Base Definitions volume of IEEE Std 1003.1-2001,
COPYRIGHT Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .