function.pcntl-signal.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Installs a signal handler</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.pcntl-setpriority.html">pcntl_setpriority</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.pcntl-wait.html">pcntl_wait</a></div> <div class="up"><a href="ref.pcntl.html">PCNTL Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.pcntl-signal" class="refentry"> <div class="refnamediv"> <h1 class="refname">pcntl_signal</h1> <p class="verinfo">(PHP 4 >= 4.0.7, PHP 5)</p><p class="refpurpose"><span class="refname">pcntl_signal</span> — <span class="dc-title">Installs a signal handler</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">bool</span> <span class="methodname"><b><b>pcntl_signal</b></b></span> ( <span class="methodparam"><span class="type">int</span> <tt class="parameter">$signo</tt></span> , <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.callback" class="type callback">callback</a></span> <tt class="parameter">$handler</tt></span> [, <span class="methodparam"><span class="type">bool</span> <tt class="parameter">$restart_syscalls</tt></span> ] )</div> <p class="para rdfs-comment"> The <b>pcntl_signal()</b> function installs a new signal handler for the signal indicated by <i><tt class="parameter">signo</tt></i>. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">signo</tt></i></span> <dd> <p class="para"> The signal number. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">handler</tt></i></span> <dd> <p class="para"> The signal handler which may be the name of a user created function, or method, or either of the two global constants <b><tt>SIG_IGN</tt></b> or <b><tt>SIG_DFL</tt></b>. </p> <blockquote><p><b class="note">Note</b>: Note that when you set a handler to an object method, that object's reference count is increased which makes it persist until you either change the handler to something else, or your script ends. <br /> </p></blockquote> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">restart_syscalls</tt></i></span> <dd> <p class="para"> Specifies whether system call restarting should be used when this signal arrives and defaults to <b><tt>TRUE</tt></b>. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns <b><tt>TRUE</tt></b> on success or <b><tt>FALSE</tt></b> on failure. </p> </div> <div class="refsect1 changelog"> <h3 class="title">ChangeLog</h3> <p class="para"> <table class="informaltable"> <colgroup> <thead valign="middle"> <tr valign="middle"> <th colspan="1">Version</th> <th colspan="1">Description</th> </tr> </thead> <tbody valign="middle" class="tbody"> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">4.3.0</td> <td colspan="1" rowspan="1" align="left"> The <i><tt class="parameter">restart_syscalls</tt></i> parameter was added. </td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">4.3.0</td> <td colspan="1" rowspan="1" align="left"> The ability to use an object method as a callback became available. </td> </tr> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">4.3.0</td> <td colspan="1" rowspan="1" align="left"> As of PHP 4.3.0 PCNTL uses ticks as the signal handle callback mechanism, which is much faster than the previous mechanism. This change follows the same semantics as using "<a href="control-structures.declare.html#control-structures.declare.ticks" class="link">user ticks</a>". You must use the <a href="control-structures.declare.html" class="link">declare()</a> statement to specify the locations in your program where callbacks are allowed to occur for the signal handler to function properly (as used in the above example). </td> </tr> </tbody> </colgroup> </table> </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 <b>pcntl_signal()</b> example</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// tick use required as of PHP 4.3.0<br /></span><span style="color: #007700">declare(</span><span style="color: #0000BB">ticks </span><span style="color: #007700">= </span><span style="color: #0000BB">1</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// signal handler function<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">sig_handler</span><span style="color: #007700">(</span><span style="color: #0000BB">$signo</span><span style="color: #007700">)<br />{<br /><br /> switch (</span><span style="color: #0000BB">$signo</span><span style="color: #007700">) {<br /> case </span><span style="color: #0000BB">SIGTERM</span><span style="color: #007700">:<br /> </span><span style="color: #FF8000">// handle shutdown tasks<br /> </span><span style="color: #007700">exit;<br /> break;<br /> case </span><span style="color: #0000BB">SIGHUP</span><span style="color: #007700">:<br /> </span><span style="color: #FF8000">// handle restart tasks<br /> </span><span style="color: #007700">break;<br /> case </span><span style="color: #0000BB">SIGUSR1</span><span style="color: #007700">:<br /> echo </span><span style="color: #DD0000">"Caught SIGUSR1...\n"</span><span style="color: #007700">;<br /> break;<br /> default:<br /> </span><span style="color: #FF8000">// handle all other signals<br /> </span><span style="color: #007700">}<br /><br />}<br /><br />echo </span><span style="color: #DD0000">"Installing signal handler...\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// setup signal handlers<br /></span><span style="color: #0000BB">pcntl_signal</span><span style="color: #007700">(</span><span style="color: #0000BB">SIGTERM</span><span style="color: #007700">, </span><span style="color: #DD0000">"sig_handler"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">pcntl_signal</span><span style="color: #007700">(</span><span style="color: #0000BB">SIGHUP</span><span style="color: #007700">, </span><span style="color: #DD0000">"sig_handler"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">pcntl_signal</span><span style="color: #007700">(</span><span style="color: #0000BB">SIGUSR1</span><span style="color: #007700">, </span><span style="color: #DD0000">"sig_handler"</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// or use an object, available as of PHP 4.3.0<br />// pcntl_signal(SIGUSR1, array($obj, "do_something");<br /><br /></span><span style="color: #007700">echo</span><span style="color: #DD0000">"Generating signal SIGTERM to self...\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// send SIGUSR1 to current process id<br /></span><span style="color: #0000BB">posix_kill</span><span style="color: #007700">(</span><span style="color: #0000BB">posix_getpid</span><span style="color: #007700">(), </span><span style="color: #0000BB">SIGUSR1</span><span style="color: #007700">);<br /><br />echo </span><span style="color: #DD0000">"Done\n"<br /><br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><a href="function.pcntl-fork.html" class="function" rel="rdfs-seeAlso">pcntl_fork()</a></li> <li class="member"><a href="function.pcntl-waitpid.html" class="function" rel="rdfs-seeAlso">pcntl_waitpid()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.pcntl-setpriority.html">pcntl_setpriority</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.pcntl-wait.html">pcntl_wait</a></div> <div class="up"><a href="ref.pcntl.html">PCNTL Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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