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

13       sem_unlink — remove a named semaphore
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SYNOPSIS

16       #include <semaphore.h>
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18       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       ENOENT The named semaphore does not exist.
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44       The sem_unlink() function may fail if:
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46       ENAMETOOLONG
47              The  length  of  the  name argument exceeds {_POSIX_PATH_MAX} on
48              systems  that  do  not  support  the  XSI  option   or   exceeds
49              {_XOPEN_PATH_MAX}  on  XSI  systems, or has a pathname component
50              that is longer than {_POSIX_NAME_MAX} on  systems  that  do  not
51              support  the  XSI option or longer than {_XOPEN_NAME_MAX} on XSI
52              systems.  A call to sem_unlink() with a name argument that  con‐
53              tains  the  same semaphore name as was previously used in a suc‐
54              cessful sem_open() call shall not give an [ENAMETOOLONG] error.
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56       The following sections are informative.
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EXAMPLES

59       None.
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APPLICATION USAGE

62       None.
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RATIONALE

65       None.
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FUTURE DIRECTIONS

68       A future version might require the sem_open()  and  sem_unlink()  func‐
69       tions to have semantics similar to normal file system operations.
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SEE ALSO

72       semctl(), semget(), semop(), sem_close(), sem_open()
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74       The Base Definitions volume of POSIX.1‐2008, <semaphore.h>
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77       Portions  of  this text are reprinted and reproduced in electronic form
78       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
79       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
80       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
81       cal  and  Electronics  Engineers,  Inc  and  The  Open Group.  (This is
82       POSIX.1-2008 with the 2013 Technical Corrigendum  1  applied.)  In  the
83       event of any discrepancy between this version and the original IEEE and
84       The Open Group Standard, the original IEEE and The Open Group  Standard
85       is  the  referee document. The original Standard can be obtained online
86       at http://www.unix.org/online.html .
87
88       Any typographical or formatting errors that appear  in  this  page  are
89       most likely to have been introduced during the conversion of the source
90       files to man page format. To report such errors,  see  https://www.ker
91       nel.org/doc/man-pages/reporting_bugs.html .
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95IEEE/The Open Group                  2013                       SEM_UNLINK(3P)
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