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<title>Seek on a gz-file pointer</title>
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<div class="refnamediv">
<h1 class="refname">gzseek</h1>
<p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">gzseek</span> — <span class="dc-title">Seek on a gz-file pointer</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.gzseek-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">int</span> <span class="methodname"><strong>gzseek</strong></span>
( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$zp</code></span>
, <span class="methodparam"><span class="type">int</span> <code class="parameter">$offset</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$whence</code><span class="initializer"> = SEEK_SET</span></span>
] )</div>
<p class="para rdfs-comment">
Sets the file position indicator for the given file pointer to the
given offset byte into the file stream. Equivalent to calling (in C)
<em>gzseek(zp, offset, SEEK_SET)</em>.
</p>
<p class="para">
If the file is opened for reading, this function is emulated but
can be extremely slow. If the file is opened for writing, only
forward seeks are supported; <span class="function"><strong>gzseek()</strong></span> then compresses
a sequence of zeroes up to the new starting position.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.gzseek-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">zp</code></em></span>
<dd>
<p class="para">
The gz-file pointer. It must be valid, and must point to a file
successfully opened by <span class="function"><a href="function.gzopen.html" class="function">gzopen()</a></span>.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">offset</code></em></span>
<dd>
<p class="para">
The seeked offset.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">whence</code></em></span>
<dd>
<p class="para">
<em><code class="parameter">whence</code></em> values are:
<ul class="simplelist">
<li class="member"><strong><code>SEEK_SET</code></strong> - Set position equal to <em><code class="parameter">offset</code></em> bytes.</li>
<li class="member"><strong><code>SEEK_CUR</code></strong> - Set position to current location plus <em><code class="parameter">offset</code></em>.</li>
</ul>
</p>
<p class="para">
If <em><code class="parameter">whence</code></em> is not specified, it is assumed to be
<strong><code>SEEK_SET</code></strong>.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.gzseek-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Upon success, returns 0; otherwise, returns -1. Note that seeking
past EOF is not considered an error.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.gzseek-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-824">
<p><strong>Example #1 <span class="function"><strong>gzseek()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$gz </span><span style="color: #007700">= </span><span style="color: #0000BB">gzopen</span><span style="color: #007700">(</span><span style="color: #DD0000">'somefile.gz'</span><span style="color: #007700">, </span><span style="color: #DD0000">'r'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">gzseek</span><span style="color: #007700">(</span><span style="color: #0000BB">$gz</span><span style="color: #007700">,</span><span style="color: #0000BB">2</span><span style="color: #007700">);<br />echo </span><span style="color: #0000BB">gzgetc</span><span style="color: #007700">(</span><span style="color: #0000BB">$gz</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">gzclose</span><span style="color: #007700">(</span><span style="color: #0000BB">$gz</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.gzseek-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.gztell.html" class="function" rel="rdfs-seeAlso">gztell()</a> - Tell gz-file pointer read/write position</span></li>
<li class="member"> <span class="function"><a href="function.gzrewind.html" class="function" rel="rdfs-seeAlso">gzrewind()</a> - Rewind the position of a gz-file pointer</span></li>
</ul>
</p>
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