Originální popis anglicky:
sem_close - close a named semaphore (
REALTIME)
Návod, kniha: POSIX Programmer's Manual
#include <semaphore.h>
int sem_close(sem_t *
sem);
The
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_unlink(), then
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.
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.
The
sem_close() function shall fail if:
- EINVAL
- The sem argument is not a valid semaphore
descriptor.
The following sections are informative.
None.
The
sem_close() function is part of the Semaphores option and need not be
available on all implementations.
None.
None.
semctl() ,
semget() ,
semop() ,
sem_init() ,
sem_open() ,
sem_unlink() , the Base Definitions volume of
IEEE Std 1003.1-2001,
<semaphore.h>
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
.
