SEM_CLOSE(3C) Standard C Library Functions SEM_CLOSE(3C)
NAME
sem_close - close a named semaphore
SYNOPSIS
#include <semaphore.h>
int sem_close(
sem_t *sem);
DESCRIPTION
The
sem_close() function is used to 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(3C)) are undefined. The
sem_close() function deallocates
(that is, make available for reuse by a subsequent
sem_open(3C) 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(3C), then
sem_close() has no effect on the state of the
semaphore. If the
sem_unlink(3C) function has been successfully
invoked for
name after the most recent call to
sem_open(3C) with
O_CREAT for this semaphore, then when all processes that have opened
the semaphore close it, the semaphore is no longer be accessible.
RETURN VALUES
If successful,
sem_close() returns
0, otherwise it returns
-1 and
sets
errno to indicate the error.
ERRORS
The
sem_close() function will fail if:
EINVAL The
sem argument is not a valid semaphore descriptor.
ENOSYS The
sem_close() function is not supported by the system.
USAGE
The
sem_close() function should not be called for an unnamed
semaphore initialized by
sem_init(3C).
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+--------------------+-------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------+
|Interface Stability | Committed |
+--------------------+-------------------+
|MT-Level | MT-Safe |
+--------------------+-------------------+
|Standard | See
standards(7). |
+--------------------+-------------------+
SEE ALSO
sem_init(3C),
sem_open(3C),
sem_unlink(3C),
attributes(7),
standards(7)NOTES
Solaris 2.6 was the first release to support the Asynchronous Input
and Output option. Prior to this release, this function always
returned
-1 and set
errno to
ENOSYS.
February 5, 2008 SEM_CLOSE(3C)
