1SEM_UNLINK(3P)             POSIX Programmer's Manual            SEM_UNLINK(3P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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NAME

12       sem_unlink - remove a named semaphore (REALTIME)
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SYNOPSIS

15       #include <semaphore.h>
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17       int sem_unlink(const char *name);
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DESCRIPTION

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

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

38       The sem_unlink() function shall fail if:
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40       EACCES Permission is denied to unlink the named semaphore.
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42       ENAMETOOLONG
43              The length of the name argument exceeds {PATH_MAX} or a pathname
44              component is longer than {NAME_MAX}.
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46       ENOENT The named semaphore does not exist.
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49       The following sections are informative.
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EXAMPLES

52       None.
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APPLICATION USAGE

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

59       None.
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FUTURE DIRECTIONS

62       None.
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SEE ALSO

65       semctl(),  semget(), semop(), sem_close(), sem_open(), the Base Defini‐
66       tions volume of IEEE Std 1003.1-2001, <semaphore.h>
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69       Portions of this text are reprinted and reproduced in  electronic  form
70       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
71       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
72       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
73       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
74       event of any discrepancy between this version and the original IEEE and
75       The Open Group Standard, the original IEEE and The Open Group  Standard
76       is  the  referee document. The original Standard can be obtained online
77       at http://www.opengroup.org/unix/online.html .
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81IEEE/The Open Group                  2003                       SEM_UNLINK(3P)
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