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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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SEM_UNLINK(3P) POSIX Programmer's Manual SEM_UNLINK(3P)
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.
sem_unlink — remove a named semaphore
#include <semaphore.h>
int sem_unlink(const char *name);
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.
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.
The sem_unlink() function shall fail if:
EACCES Permission is denied to unlink the named semaphore.
ENOENT The named semaphore does not exist.
The sem_unlink() function may fail if:
ENAMETOOLONG
The length of the name argument exceeds {_POSIX_PATH_MAX}
on systems that do not support the XSI option or exceeds
{_XOPEN_PATH_MAX} on XSI systems, or has a pathname
component that is longer than {_POSIX_NAME_MAX} on systems
that do not support the XSI option or longer than
{_XOPEN_NAME_MAX} on XSI systems. A call to sem_unlink()
with a name argument that contains the same semaphore name
as was previously used in a successful sem_open() call
shall not give an [ENAMETOOLONG] error.
The following sections are informative.
None.
None.
None.
A future version might require the sem_open() and sem_unlink()
functions to have semantics similar to normal file system
operations.
semctl(3p), semget(3p), semop(3p), sem_close(3p), sem_open(3p)
The Base Definitions volume of POSIX.1‐2017, semaphore.h(0p)
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 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 .
Any typographical or formatting errors that appear in this page
are most likely to have been introduced during the conversion of
the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2017 SEM_UNLINK(3P)
Pages that refer to this page: semaphore.h(0p), sem_close(3p), semctl(3p), semget(3p), semop(3p), sem_open(3p)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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