IPC::Semaphore - SysV Semaphore IPC object class

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A new set is created if</p> <ul> <li><p><code>KEY</code> is equal to <code>IPC_PRIVATE</code></p> </li> <li><p><code>KEY</code> does not already have a semaphore identifier associated with it, and <code><i>FLAGS</i> & IPC_CREAT</code> is true.</p> </li> </ul> <p>On creation of a new semaphore set <code>FLAGS</code> is used to set the permissions. Be careful not to set any flags that the Sys V IPC implementation does not allow: in some systems setting execute bits makes the operations fail.</p> </dd> <dt id="getall"><a class="permalink" href="#getall">#</a>getall</dt> <dd> <p>Returns the values of the semaphore set as an array.</p> </dd> <dt id="getncnt-(-SEM-)"><a class="permalink" href="#getncnt-(-SEM-)">#</a><a id="getncnt"></a><a id="getncnt-SEM"></a>getncnt ( SEM )</dt> <dd> <p>Returns the number of processes waiting for the semaphore <code>SEM</code> to become greater than its current value</p> </dd> <dt id="getpid-(-SEM-)"><a class="permalink" href="#getpid-(-SEM-)">#</a><a id="getpid"></a><a id="getpid-SEM"></a>getpid ( SEM )</dt> <dd> <p>Returns the process id of the last process that performed an operation on the semaphore <code>SEM</code>.</p> </dd> <dt id="getval-(-SEM-)"><a class="permalink" href="#getval-(-SEM-)">#</a><a id="getval"></a><a id="getval-SEM"></a>getval ( SEM )</dt> <dd> <p>Returns the current value of the semaphore <code>SEM</code>.</p> </dd> <dt id="getzcnt-(-SEM-)"><a class="permalink" href="#getzcnt-(-SEM-)">#</a><a id="getzcnt"></a><a id="getzcnt-SEM"></a>getzcnt ( SEM )</dt> <dd> <p>Returns the number of processes waiting for the semaphore <code>SEM</code> to become zero.</p> </dd> <dt id="id"><a class="permalink" href="#id">#</a>id</dt> <dd> <p>Returns the system identifier for the semaphore set.</p> </dd> <dt id="op-(-OPLIST-)"><a class="permalink" href="#op-(-OPLIST-)">#</a><a id="op"></a><a id="op-OPLIST"></a>op ( OPLIST )</dt> <dd> <p><code>OPLIST</code> is a list of operations to pass to <code>semop</code>. <code>OPLIST</code> is a concatenation of smaller lists, each which has three values. The first is the semaphore number, the second is the operation and the last is a flags value. See <a href="http://man.he.net/man2/semop">semop(2)</a> for more details. For example</p> <pre><code> $sem->op( 0, -1, IPC_NOWAIT, 1, 1, IPC_NOWAIT );</code></pre> </dd> <dt id="remove"><a class="permalink" href="#remove">#</a>remove</dt> <dd> <p>Remove and destroy the semaphore set from the system.</p> </dd> <dt id="set-(-STAT-)"><a class="permalink" href="#set-(-STAT-)">#</a><a id="set"></a><a id="set-STAT"></a>set ( STAT )</dt> <dd> </dd> <dt id="set-(-NAME-=>-VALUE-[,-NAME-=>-VALUE-...]-)"><a class="permalink" href="#set-(-NAME-=%3E-VALUE-%5B,-NAME-=%3E-VALUE-...%5D-)">#</a><a id="set1"></a><a id="set-NAME-VALUE-NAME-VALUE"></a>set ( NAME => VALUE [, NAME => VALUE ...] )</dt> <dd> <p><code>set</code> will set the following values of the <code>stat</code> structure associated with the semaphore set.</p> <pre><code class="plaintext">uid gid mode (only the permission bits)</code></pre> <p><code>set</code> accepts either a stat object, as returned by the <code>stat</code> method, or a list of <i>name</i>-<i>value</i> pairs.</p> </dd> <dt id="setall-(-VALUES-)"><a class="permalink" href="#setall-(-VALUES-)">#</a><a id="setall"></a><a id="setall-VALUES"></a>setall ( VALUES )</dt> <dd> <p>Sets all values in the semaphore set to those given on the <code>VALUES</code> list. <code>VALUES</code> must contain the correct number of values.</p> </dd> <dt id="setval-(-N-,-VALUE-)"><a class="permalink" href="#setval-(-N-,-VALUE-)">#</a><a id="setval"></a><a id="setval-N-VALUE"></a>setval ( N , VALUE )</dt> <dd> <p>Set the <code>N</code>th value in the semaphore set to <code>VALUE</code></p> </dd> <dt id="stat"><a class="permalink" href="#stat">#</a>stat</dt> <dd> <p>Returns an object of type <code>IPC::Semaphore::stat</code> which is a sub-class of <code>Class::Struct</code>. It provides the following fields. For a description of these fields see your system documentation.</p> <pre><code class="plaintext">uid gid cuid cgid mode ctime otime nsems</code></pre> </dd> </dl> <h1 id="SEE-ALSO"><a class="permalink" href="#SEE-ALSO">#</a><a id="SEE"></a>SEE ALSO</h1> <p><a href="/5.36.0/IPC::SysV">IPC::SysV</a>, <a href="/5.36.0/Class::Struct">Class::Struct</a>, <a href="http://man.he.net/man2/semget">semget(2)</a>, <a href="http://man.he.net/man2/semctl">semctl(2)</a>, <a href="http://man.he.net/man2/semop">semop(2)</a></p> <h1 id="AUTHORS"><a class="permalink" href="#AUTHORS">#</a>AUTHORS</h1> <p>Graham Barr <gbarr@pobox.com>, Marcus Holland-Moritz <mhx@cpan.org></p> <h1 id="COPYRIGHT"><a class="permalink" href="#COPYRIGHT">#</a>COPYRIGHT</h1> <p>Version 2.x, Copyright (C) 2007-2013, Marcus Holland-Moritz.</p> <p>Version 1.x, Copyright (c) 1997, Graham Barr.</p> <p>This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.</p> </div> <div id="footer"> <p>Perldoc Browser is maintained by Dan Book (<a href="https://metacpan.org/author/DBOOK">DBOOK</a>). 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IPC::Semaphore - SysV Semaphore IPC object class - Perldoc Browser