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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><!-- Copyright 1997 The Open Group, All Rights Reserved --><title>sem_unlink</title></head><body bgcolor=white><center><font size=2>The Single UNIX ® Specification, Version 2<br>Copyright © 1997 The Open Group</font></center><hr size=2 noshade><h4><a name = "tag_000_008_333"> </a>NAME</h4><blockquote>sem_unlink - remove a named semaphore(<b>REALTIME</b>)</blockquote><h4><a name = "tag_000_008_334"> </a>SYNOPSIS</h4><blockquote><pre><code>#include <<a href="semaphore.h.html">semaphore.h</a>>int sem_unlink(const char *<i>name</i>);</code></pre></blockquote><h4><a name = "tag_000_008_335"> </a>DESCRIPTION</h4><blockquote>The<i>sem_unlink()</i>function removes the semaphore named by the string<i>name</i>.If the semaphore named by<i>name</i>is currently referenced by other processes, then<i>sem_unlink()</i>has no effect on the state of the semaphore. If one or more processeshave the semaphore open when<i>sem_unlink()</i>is called, destruction of the semaphore is postponed untilall references to the semaphore have been destroyed by calls to<i><a href="sem_close.html">sem_close()</a></i>,<i><a href="_exit.html">_exit()</a></i>,or<i>exec</i>.Calls to<i><a href="sem_open.html">sem_open()</a></i>to re-create or re-connect to the semaphore refer to a new semaphoreafter <i>sem_unlink()</i>is called. The<i>sem_unlink()</i>call does not block until all references have been destroyed; itreturns immediately.</blockquote><h4><a name = "tag_000_008_336"> </a>RETURN VALUE</h4><blockquote>Upon successful completion, the function returns a value of 0.Otherwise, the semaphore is not changed and thefunction returns a value of -1 and sets<i>errno</i>to indicate the error.</blockquote><h4><a name = "tag_000_008_337"> </a>ERRORS</h4><blockquote>The <i>sem_unlink()</i>function will fail if:<dl compact><dt>[EACCES]<dd>Permission is denied to unlink the named semaphore.<dt>[ENAMETOOLONG]<dd>The length of the<i>name</i>string exceeds {NAME_MAX} while {POSIX_NO_TRUNC} is in effect.<dt>[ENOENT]<dd>The named semaphore does not exist.<dt>[ENOSYS]<dd>The function<i>sem_unlink()</i>is not supported by this implementation.</dl></blockquote><h4><a name = "tag_000_008_338"> </a>EXAMPLES</h4><blockquote>None.</blockquote><h4><a name = "tag_000_008_339"> </a>APPLICATION USAGE</h4><blockquote>None.</blockquote><h4><a name = "tag_000_008_340"> </a>FUTURE DIRECTIONS</h4><blockquote>None.</blockquote><h4><a name = "tag_000_008_341"> </a>SEE ALSO</h4><blockquote><i><a href="semctl.html">semctl()</a></i>,<i><a href="semget.html">semget()</a></i>,<i><a href="semop.html">semop()</a></i>,<i><a href="sem_close.html">sem_close()</a></i>,<i><a href="sem_open.html">sem_open()</a></i>,<i><a href="semaphore.h.html"><semaphore.h></a></i>.</blockquote><h4>DERIVATION</h4><blockquote>Derived from the POSIX Realtime Extension (1003.1b-1993/1003.1i-1995)</blockquote><hr size=2 noshade><center><font size=2>UNIX ® is a registered Trademark of The Open Group.<br>Copyright © 1997 The Open Group<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]</font></center><hr size=2 noshade></body></html>⌨️ 快捷键说明
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