SEM_UNLINK(3P)

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_unlink - remove a named semaphore (REALTIME)

SYNOPSIS

#include <semaphore.h>

int sem_unlink(const char *name);

DESCRIPTION

The sem_unlink() function shall remove the semaphore named by the string name. If the semaphore named by name is currently referenced by other processes, then sem_unlink() shall have no effect on the state of the semaphore. If one or more processes have the semaphore open when sem_unlink() is called, destruction of the semaphore is postponed until all references to the semaphore have been destroyed by calls to sem_close(), _exit(), or exec. Calls to sem_open() to recreate or reconnect to the semaphore refer to a new semaphore after sem_unlink() is called. The sem_unlink() call shall not block until all references have been destroyed; it shall return immediately.

RETURN VALUE

Upon successful completion, the sem_unlink() function shall return a value of 0. Otherwise, the semaphore shall not be changed and the function shall return a value of -1 and set errno to indicate the error.

ERRORS

The sem_unlink() function shall fail if:

EACCES
    Permission is denied to unlink the named semaphore.

ENAMETOOLONG
    The length of the name argument exceeds {PATH_MAX} or a pathname component is longer than {NAME_MAX}.

ENOENT
    The named semaphore does not exist.

The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

The sem_unlink() function is part of the Semaphores option and need not be available on all implementations.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

semctl(), semget(), semop(), sem_close(), sem_open(), the Base Definitions volume of IEEE Std 1003.1-2001, <semaphore.h>

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 .