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<div class="refnamediv">
<h1 class="refname">substr_compare</h1>
<p class="verinfo">(PHP 5)</p><p class="refpurpose"><span class="refname">substr_compare</span> — <span class="dc-title">Binary safe comparison of two strings from an offset, up to length characters</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.substr-compare-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">int</span> <span class="methodname"><strong>substr_compare</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$main_str</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$str</code></span>
, <span class="methodparam"><span class="type">int</span> <code class="parameter">$offset</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$length</code></span>
[, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$case_insensitivity</code><span class="initializer"> = false</span></span>
]] )</div>
<p class="para rdfs-comment">
<span class="function"><strong>substr_compare()</strong></span> compares <em><code class="parameter">main_str</code></em>
from position <em><code class="parameter">offset</code></em> with <em><code class="parameter">str</code></em>
up to <em><code class="parameter">length</code></em> characters.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.substr-compare-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">main_str</code></em></span>
<dd>
<p class="para">
The main string being compared.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">str</code></em></span>
<dd>
<p class="para">
The secondary string being compared.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">offset</code></em></span>
<dd>
<p class="para">
The start position for the comparison. If negative, it starts counting
from the end of the string.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">length</code></em></span>
<dd>
<p class="para">
The length of the comparison. The default value is the largest of the
length of the <em><code class="parameter">str</code></em> compared to the length of
<em><code class="parameter">main_str</code></em> less the
<em><code class="parameter">offset</code></em>.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">case_insensitivity</code></em></span>
<dd>
<p class="para">
If <em><code class="parameter">case_insensitivity</code></em> is <strong><code>TRUE</code></strong>, comparison is
case insensitive.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.substr-compare-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns < 0 if <em><code class="parameter">main_str</code></em> from position
<em><code class="parameter">offset</code></em> is less than <em><code class="parameter">str</code></em>, >
0 if it is greater than <em><code class="parameter">str</code></em>, and 0 if they are equal.
If <em><code class="parameter">offset</code></em> is equal to or greater than the length of
<em><code class="parameter">main_str</code></em> or <em><code class="parameter">length</code></em> is set and
is less than 1, <span class="function"><strong>substr_compare()</strong></span> prints a warning and returns
<strong><code>FALSE</code></strong>.
</p>
</div>
<div class="refsect1 changelog" id="refsect1-function.substr-compare-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>5.1.0</td>
<td>
Added the possibility to use a negative <em><code class="parameter">offset</code></em>.
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.substr-compare-examples">
<h3 class="title">Examples</h3>
<p class="para">
<div class="example" id="example-4913">
<p><strong>Example #1 A <span class="function"><strong>substr_compare()</strong></span> example</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">substr_compare</span><span style="color: #007700">(</span><span style="color: #DD0000">"abcde"</span><span style="color: #007700">, </span><span style="color: #DD0000">"bc"</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">); </span><span style="color: #FF8000">// 0<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">substr_compare</span><span style="color: #007700">(</span><span style="color: #DD0000">"abcde"</span><span style="color: #007700">, </span><span style="color: #DD0000">"de"</span><span style="color: #007700">, -</span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">); </span><span style="color: #FF8000">// 0<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">substr_compare</span><span style="color: #007700">(</span><span style="color: #DD0000">"abcde"</span><span style="color: #007700">, </span><span style="color: #DD0000">"bcg"</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">); </span><span style="color: #FF8000">// 0<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">substr_compare</span><span style="color: #007700">(</span><span style="color: #DD0000">"abcde"</span><span style="color: #007700">, </span><span style="color: #DD0000">"BC"</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">); </span><span style="color: #FF8000">// 0<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">substr_compare</span><span style="color: #007700">(</span><span style="color: #DD0000">"abcde"</span><span style="color: #007700">, </span><span style="color: #DD0000">"bc"</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">); </span><span style="color: #FF8000">// 1<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">substr_compare</span><span style="color: #007700">(</span><span style="color: #DD0000">"abcde"</span><span style="color: #007700">, </span><span style="color: #DD0000">"cd"</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">); </span><span style="color: #FF8000">// -1<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">substr_compare</span><span style="color: #007700">(</span><span style="color: #DD0000">"abcde"</span><span style="color: #007700">, </span><span style="color: #DD0000">"abc"</span><span style="color: #007700">, </span><span style="color: #0000BB">5</span><span style="color: #007700">, </span><span style="color: #0000BB">1</span><span style="color: #007700">); </span><span style="color: #FF8000">// warning<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
</div>
<div class="refsect1 seealso" id="refsect1-function.substr-compare-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.strncmp.html" class="function" rel="rdfs-seeAlso">strncmp()</a> - Binary safe string comparison of the first n characters</span></li>
</ul>
</p>
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