Manual page for sem_close(3R)
sem_close - close a named semaphore
SYNOPSIS
cc
[ flag ... ] file ...
-lposix4
[ library ... ]
#include <semaphore.h>
int sem_close(sem_t *sem);
typedef struct {
...
} sem_t; /*opaque POSIX.4 semaphore*/
MT-LEVEL
MT-Safe
DESCRIPTION
sem_close()
is used to indicate that the calling process is finished
using the named semaphore
sem.
sem_close()
deallocates any system resources for use by this process for this semaphore.
If the semaphore has not been removed with a successful call to
sem_unlink.3r
then
sem_close()
has no effect on the state of the semaphore.
If
sem_unlink.3r
has been successfully invoked for
name
after the most recent call to
sem_open.3r
with O_CREAT
for this semaphore,
then when all processes that have opened the semaphore close it, the semaphore will no longer be accessible.
sem_close()
should not be called for an unnamed semaphore initialized by
sem_init.3r
RETURN VALUES
If successful,
sem_close()
returns
0,
otherwise it returns
-1
and sets
errno
to indicate the error condition.
ERRORS
- EINVAL
-
sem
is not a valid semaphore descriptor.
- ENOSYS
-
sem_close()
is not supported by this implementation.
SEE ALSO
sem_init.3r
sem_open.3r
sem_unlink.3r
BUGS
In Solaris 2.5, these functions always return -1 and set
errno
to
ENOSYS,
because this release does not support the
Semaphores option.
It is our intention to provide support
for these interfaces in future releases.
Created by unroff & hp-tools.
© by Hans-Peter Bischof. All Rights Reserved (1997).
Last modified 21/April/97
