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</div><hr /><div id="function.sleep" class="refentry">
<div class="refnamediv">
<h1 class="refname">sleep</h1>
<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">sleep</span> — <span class="dc-title">Delay execution</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.sleep-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">int</span> <span class="methodname"><strong>sleep</strong></span>
( <span class="methodparam"><span class="type">int</span> <code class="parameter">$seconds</code></span>
)</div>
<p class="simpara">
Delays the program execution for the given number of
<em><code class="parameter">seconds</code></em>.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.sleep-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">seconds</code></em></span>
<dd>
<p class="para">
Halt time in seconds.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.sleep-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns zero on success, or <strong><code>FALSE</code></strong> on error.
</p>
<p class="para">
If the call was interrupted by a signal, <span class="function"><strong>sleep()</strong></span> returns
a non-zero value. On Windows, this value will always be
<em>192</em> (the value of the
<strong><code>WAIT_IO_COMPLETION</code></strong> constant within the Windows API).
On other platforms, the return value will be the number of seconds left to
sleep.
</p>
</div>
<div class="refsect1 errors" id="refsect1-function.sleep-errors">
<h3 class="title">Errors/Exceptions</h3>
<p class="para">
If the specified number of <em><code class="parameter">seconds</code></em> is negative,
this function will generate a <strong><code>E_WARNING</code></strong>.
</p>
</div>
<div class="refsect1 changelog" id="refsect1-function.sleep-changelog">
<h3 class="title">Changelog</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>5.3.4</td>
<td>
Before PHP 5.3.4, on Windows, <span class="function"><strong>sleep()</strong></span> always
returns <strong><code>NULL</code></strong> when sleep has occurred, regardless of whether the
sleep was interrupted or not.
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.sleep-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-3784">
<p><strong>Example #1 <span class="function"><strong>sleep()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br /></span><span style="color: #FF8000">// current time<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">date</span><span style="color: #007700">(</span><span style="color: #DD0000">'h:i:s'</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// sleep for 10 seconds<br /></span><span style="color: #0000BB">sleep</span><span style="color: #007700">(</span><span style="color: #0000BB">10</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">// wake up !<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">date</span><span style="color: #007700">(</span><span style="color: #DD0000">'h:i:s'</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>
This example will output (after 10 seconds)
</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
05:31:23
05:31:33
</pre></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.sleep-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.usleep.html" class="function" rel="rdfs-seeAlso">usleep()</a> - Delay execution in microseconds</span></li>
<li class="member"> <span class="function"><a href="function.time-nanosleep.html" class="function" rel="rdfs-seeAlso">time_nanosleep()</a> - Delay for a number of seconds and nanoseconds</span></li>
<li class="member"> <span class="function"><a href="function.time-sleep-until.html" class="function" rel="rdfs-seeAlso">time_sleep_until()</a> - Make the script sleep until the specified time</span></li>
<li class="member"> <span class="function"><a href="function.set-time-limit.html" class="function" rel="rdfs-seeAlso">set_time_limit()</a> - Limits the maximum execution time</span></li>
</ul>
</p>
</div>
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