<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>Compares two "PHP-standardized" version number strings</title>
</head>
<body><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="function.sys-get-temp-dir.html">sys_get_temp_dir</a></div>
<div class="next" style="text-align: right; float: right;"><a href="function.zend-logo-guid.html">zend_logo_guid</a></div>
<div class="up"><a href="ref.info.html">PHP Options/Info Functions</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div><hr /><div id="function.version-compare" class="refentry">
<div class="refnamediv">
<h1 class="refname">version_compare</h1>
<p class="verinfo">(PHP 4 >= 4.1.0, PHP 5)</p><p class="refpurpose"><span class="refname">version_compare</span> — <span class="dc-title">Compares two "PHP-standardized" version number strings</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.version-compare-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"><strong>version_compare</strong></span>
( <span class="methodparam"><span class="type">string</span> <code class="parameter">$version1</code></span>
, <span class="methodparam"><span class="type">string</span> <code class="parameter">$version2</code></span>
[, <span class="methodparam"><span class="type">string</span> <code class="parameter">$operator</code></span>
] )</div>
<p class="para rdfs-comment">
<span class="function"><strong>version_compare()</strong></span> compares two "PHP-standardized"
version number strings. This is useful if you would like to write programs
working only on some versions of PHP.
</p>
<p class="para">
The function first replaces <em>_</em>, <em>-</em> and
<em>+</em> with a dot <em>.</em> in the version
strings and also inserts dots <em>.</em> before and after any
non number so that for example '4.3.2RC1' becomes '4.3.2.RC.1'. Then it
splits the results like if you were using explode('.', $ver). Then it
compares the parts starting from left to right. If a part contains
special version strings these are handled in the following order:
<em>any string not found in this list</em> <
<em>dev</em> < <em>alpha</em> =
<em>a</em> < <em>beta</em> =
<em>b</em> < <em>RC</em> =
<em>rc</em> < <em>#</em> <
<em>pl</em> = <em>p</em>. This way not only versions
with different levels like '4.1' and '4.1.2' can be compared but also any
PHP specific version containing development state.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.version-compare-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">version1</code></em></span>
<dd>
<p class="para">
First version number.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">version2</code></em></span>
<dd>
<p class="para">
Second version number.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">operator</code></em></span>
<dd>
<p class="para">
If you specify the third optional <em><code class="parameter">operator</code></em>
argument, you can test for a particular relationship. The
possible operators are: <em><</em>,
<em>lt</em>, <em><=</em>,
<em>le</em>, <em>></em>,
<em>gt</em>, <em>>=</em>,
<em>ge</em>, <em>==</em>,
<em>=</em>, <em>eq</em>,
<em>!=</em>, <em><></em>,
<em>ne</em> respectively.
</p>
<p class="para">
This parameter is case-sensitive, so values should be lowercase.
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.version-compare-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
By default, <span class="function"><strong>version_compare()</strong></span> returns
<em>-1</em> if the first version is lower than the second,
<em>0</em> if they are equal, and
<em>1</em> if the second is lower.
</p>
<p class="para">
When using the optional <em><code class="parameter">operator</code></em> argument, the
function will return <strong><code>TRUE</code></strong> if the relationship is the one specified
by the operator, <strong><code>FALSE</code></strong> otherwise.
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.version-compare-examples">
<h3 class="title">Examples</h3>
<p class="para">
The examples below use the <strong><code>PHP_VERSION</code></strong> constant,
because it contains the value of the PHP version that is executing
the code.
</p>
<p class="para">
<div class="example" id="example-523">
<p><strong>Example #1 <span class="function"><strong>version_compare()</strong></span> examples</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">if (</span><span style="color: #0000BB">version_compare</span><span style="color: #007700">(</span><span style="color: #0000BB">PHP_VERSION</span><span style="color: #007700">, </span><span style="color: #DD0000">'6.0.0'</span><span style="color: #007700">) >= </span><span style="color: #0000BB">0</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">'I am at least PHP version 6.0.0, my version: ' </span><span style="color: #007700">. </span><span style="color: #0000BB">PHP_VERSION </span><span style="color: #007700">. </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />}<br /><br />if (</span><span style="color: #0000BB">version_compare</span><span style="color: #007700">(</span><span style="color: #0000BB">PHP_VERSION</span><span style="color: #007700">, </span><span style="color: #DD0000">'5.3.0'</span><span style="color: #007700">) >= </span><span style="color: #0000BB">0</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">'I am at least PHP version 5.3.0, my version: ' </span><span style="color: #007700">. </span><span style="color: #0000BB">PHP_VERSION </span><span style="color: #007700">. </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />}<br /><br />if (</span><span style="color: #0000BB">version_compare</span><span style="color: #007700">(</span><span style="color: #0000BB">PHP_VERSION</span><span style="color: #007700">, </span><span style="color: #DD0000">'5.0.0'</span><span style="color: #007700">, </span><span style="color: #DD0000">'>='</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">'I am using PHP 5, my version: ' </span><span style="color: #007700">. </span><span style="color: #0000BB">PHP_VERSION </span><span style="color: #007700">. </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />}<br /><br />if (</span><span style="color: #0000BB">version_compare</span><span style="color: #007700">(</span><span style="color: #0000BB">PHP_VERSION</span><span style="color: #007700">, </span><span style="color: #DD0000">'5.0.0'</span><span style="color: #007700">, </span><span style="color: #DD0000">'<'</span><span style="color: #007700">)) {<br /> echo </span><span style="color: #DD0000">'I am using PHP 4, my version: ' </span><span style="color: #007700">. </span><span style="color: #0000BB">PHP_VERSION </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>
</p>
</div>
<div class="refsect1 notes" id="refsect1-function.version-compare-notes">
<h3 class="title">Notes</h3>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
The <strong><code>PHP_VERSION</code></strong> constant holds current PHP version.
</p>
</p></blockquote>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
Note that pre-release versions, such as 5.3.0-dev, are considered
lower than their final release counterparts (like 5.3.0).
</p>
</p></blockquote>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
Special version strings such as <em>alpha</em> and
<em>beta</em> are case sensitive. Version strings from arbitrary
sources that do not adhere to the PHP standard may need to be lowercased
via <span class="function"><a href="function.strtolower.html" class="function">strtolower()</a></span> before calling
<span class="function"><strong>version_compare()</strong></span>.
</p>
</p></blockquote>
</div>
<div class="refsect1 seealso" id="refsect1-function.version-compare-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.phpversion.html" class="function" rel="rdfs-seeAlso">phpversion()</a> - Gets the current PHP version</span></li>
<li class="member"> <span class="function"><a href="function.php-uname.html" class="function" rel="rdfs-seeAlso">php_uname()</a> - Returns information about the operating system PHP is running on</span></li>
<li class="member"> <span class="function"><a href="function.function-exists.html" class="function" rel="rdfs-seeAlso">function_exists()</a> - Return TRUE if the given function has been defined</span></li>
</ul>
</p>
</div>
</div><hr /><div class="manualnavbar" style="text-align: center;">
<div class="prev" style="text-align: left; float: left;"><a href="function.sys-get-temp-dir.html">sys_get_temp_dir</a></div>
<div class="next" style="text-align: right; float: right;"><a href="function.zend-logo-guid.html">zend_logo_guid</a></div>
<div class="up"><a href="ref.info.html">PHP Options/Info Functions</a></div>
<div class="home"><a href="index.html">PHP Manual</a></div>
</div></body></html>
