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<div class="refnamediv">
<h1 class="refname">SplFileObject::flock</h1>
<p class="verinfo">(PHP 5 >= 5.1.0, PHP 7)</p><p class="refpurpose"><span class="refname">SplFileObject::flock</span> — <span class="dc-title">Portable file locking</span></p>
</div>
<div class="refsect1 description" id="refsect1-splfileobject.flock-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="modifier">public</span> <span class="type">bool</span> <span class="methodname"><strong>SplFileObject::flock</strong></span>
( <span class="methodparam"><span class="type">int</span> <code class="parameter">$operation</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter reference">&$wouldblock</code></span>
] )</div>
<p class="para rdfs-comment">
Locks or unlocks the file in the same portable way as <span class="function"><a href="function.flock.html" class="function">flock()</a></span>.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-splfileobject.flock-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<code class="parameter">operation</code></dt>
<dd>
<p class="para">
<code class="parameter">operation</code> is one of the following:
<ul class="itemizedlist">
<li class="listitem">
<span class="simpara">
<strong><code>LOCK_SH</code></strong> to acquire a shared lock (reader).
</span>
</li>
<li class="listitem">
<span class="simpara">
<strong><code>LOCK_EX</code></strong> to acquire an exclusive lock (writer).
</span>
</li>
<li class="listitem">
<span class="simpara">
<strong><code>LOCK_UN</code></strong> to release a lock (shared or exclusive).
</span>
</li>
<li class="listitem">
<span class="simpara">
<strong><code>LOCK_NB</code></strong> to not block while locking.
</span>
</li>
</ul>
</p>
</dd>
<dt>
<code class="parameter">wouldblock</code></dt>
<dd>
<p class="para">
Set to <strong><code>TRUE</code></strong> if the lock would block (EWOULDBLOCK errno condition).
</p>
</dd>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-splfileobject.flock-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns <strong><code>TRUE</code></strong> on success or <strong><code>FALSE</code></strong> on failure.
</p>
</div>
<div class="refsect1 examples" id="refsect1-splfileobject.flock-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-4884">
<p><strong>Example #1 <span class="methodname"><strong>SplFileObject::flock()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$file </span><span style="color: #007700">= new </span><span style="color: #0000BB">SplFileObject</span><span style="color: #007700">(</span><span style="color: #DD0000">"/tmp/lock.txt"</span><span style="color: #007700">, </span><span style="color: #DD0000">"w"</span><span style="color: #007700">);<br />if (</span><span style="color: #0000BB">$file</span><span style="color: #007700">-></span><span style="color: #0000BB">flock</span><span style="color: #007700">(</span><span style="color: #0000BB">LOCK_EX</span><span style="color: #007700">)) { </span><span style="color: #FF8000">// do an exclusive lock<br /> </span><span style="color: #0000BB">$file</span><span style="color: #007700">-></span><span style="color: #0000BB">ftruncate</span><span style="color: #007700">(</span><span style="color: #0000BB">0</span><span style="color: #007700">); </span><span style="color: #FF8000">// truncate file<br /> </span><span style="color: #0000BB">$file</span><span style="color: #007700">-></span><span style="color: #0000BB">fwrite</span><span style="color: #007700">(</span><span style="color: #DD0000">"Write something here\n"</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$file</span><span style="color: #007700">-></span><span style="color: #0000BB">flock</span><span style="color: #007700">(</span><span style="color: #0000BB">LOCK_UN</span><span style="color: #007700">); </span><span style="color: #FF8000">// release the lock <br /></span><span style="color: #007700">} else {<br /> echo </span><span style="color: #DD0000">"Couldn't get the lock!"</span><span style="color: #007700">;<br />}<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 changelog" id="refsect1-splfileobject.flock-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>5.5.22, 5.6.6</td>
<td>
Added support for the <code class="parameter">wouldblock</code> parameter on
Windows.
</td>
</tr>
<tr>
<td>5.3.2</td>
<td>
The automatic unlocking when the file's resource handle is closed was
removed. Unlocking now always has to be done manually.
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-splfileobject.flock-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.flock.html" class="function" rel="rdfs-seeAlso">flock()</a> - Portable advisory file locking</span></li>
</ul>
</p>
</div>
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