function.microtime.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>Return current Unix timestamp with microseconds</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.localtime.html">localtime</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.mktime.html">mktime</a></div> <div class="up"><a href="ref.datetime.html">Date/Time Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.microtime" class="refentry"> <div class="refnamediv"> <h1 class="refname">microtime</h1> <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">microtime</span> — <span class="dc-title">Return current Unix timestamp with microseconds</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <span class="methodname"><b><b>microtime</b></b></span> ([ <span class="methodparam"><span class="type">bool</span> <tt class="parameter">$get_as_float</tt></span> ] )</div> <p class="para rdfs-comment"> <b>microtime()</b> returns the current Unix timestamp with microseconds. This function is only available on operating systems that support the gettimeofday() system call. </p> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">get_as_float</tt></i></span> <dd> <p class="para"> When called without the optional argument, this function returns the string "msec sec" where sec is the current time measured in the number of seconds since the Unix Epoch (0:00:00 January 1, 1970 GMT), and msec is the microseconds part. Both portions of the string are returned in units of seconds. </p> <p class="para"> If the optional <i><tt class="parameter">get_as_float</tt></i> is set to <b><tt>TRUE</tt></b> then a <a href="language.types.float.html" class="type float">float</a> (in seconds) is returned. </p> </dd> </dt> </dl> </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">5.0.0</td> <td colspan="1" rowspan="1" align="left"> The <i><tt class="parameter">get_as_float</tt></i> parameter was added. </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 Timing script execution with <b>microtime()</b></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">/**<br /> * Simple function to replicate PHP 5 behaviour<br /> */<br /></span><span style="color: #007700">function </span><span style="color: #0000BB">microtime_float</span><span style="color: #007700">()<br />{<br /> list(</span><span style="color: #0000BB">$usec</span><span style="color: #007700">, </span><span style="color: #0000BB">$sec</span><span style="color: #007700">) = </span><span style="color: #0000BB">explode</span><span style="color: #007700">(</span><span style="color: #DD0000">" "</span><span style="color: #007700">, </span><span style="color: #0000BB">microtime</span><span style="color: #007700">());<br /> return ((float)</span><span style="color: #0000BB">$usec </span><span style="color: #007700">+ (float)</span><span style="color: #0000BB">$sec</span><span style="color: #007700">);<br />}<br /><br /></span><span style="color: #0000BB">$time_start </span><span style="color: #007700">= </span><span style="color: #0000BB">microtime_float</span><span style="color: #007700">();<br /><br /></span><span style="color: #FF8000">// Sleep for a while<br /></span><span style="color: #0000BB">usleep</span><span style="color: #007700">(</span><span style="color: #0000BB">100</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$time_end </span><span style="color: #007700">= </span><span style="color: #0000BB">microtime_float</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">$time </span><span style="color: #007700">= </span><span style="color: #0000BB">$time_end </span><span style="color: #007700">- </span><span style="color: #0000BB">$time_start</span><span style="color: #007700">;<br /><br />echo </span><span style="color: #DD0000">"Did nothing in $time seconds\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> <div class="example"> <p><b>Example #2 Timing script execution in PHP 5</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br />$time_start </span><span style="color: #007700">= </span><span style="color: #0000BB">microtime</span><span style="color: #007700">(</span><span style="color: #0000BB">true</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// Sleep for a while<br /></span><span style="color: #0000BB">usleep</span><span style="color: #007700">(</span><span style="color: #0000BB">100</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$time_end </span><span style="color: #007700">= </span><span style="color: #0000BB">microtime</span><span style="color: #007700">(</span><span style="color: #0000BB">true</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$time </span><span style="color: #007700">= </span><span style="color: #0000BB">$time_end </span><span style="color: #007700">- </span><span style="color: #0000BB">$time_start</span><span style="color: #007700">;<br /><br />echo </span><span style="color: #DD0000">"Did nothing in $time seconds\n"</span><span style="color: #007700">;<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.time.html" class="function" rel="rdfs-seeAlso">time()</a></li> </ul> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.localtime.html">localtime</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.mktime.html">mktime</a></div> <div class="up"><a href="ref.datetime.html">Date/Time 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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