PHP 选项/信息 函数
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phpversion

(PHP 4, PHP 5)

phpversion — Gets the current PHP version

说明

string phpversion ([ string $extension ] )

Returns a string containing the version of the currently running PHP parser or extension.

参数

extension

An optional extension name.

返回值

If the optional extension parameter is specified, phpversion() returns the version of that extension, or FALSE if there is no version information associated or the extension isn't enabled.

范例

Example #1 phpversion() example

<?php
// prints e.g. 'Current PHP version: 4.1.1'
echo 'Current PHP version: ' . phpversion();

// prints e.g. '2.0' or nothing if the extension isn't enabled
echo phpversion('tidy');
?>

Example #2 PHP_VERSION_ID example and usage

<?php
// PHP_VERSION_ID is available as of PHP 5.2.7, if our 
// version is lower than that, then emulate it
if (!defined('PHP_VERSION_ID')) {
    $version = explode('.', PHP_VERSION);

    define('PHP_VERSION_ID', ($version[0] * 10000 + $version[1] * 100 + $version[2]));
}

// PHP_VERSION_ID is defined as a number, where the higher the number 
// is, the newer a PHP version is used. It's defined as used in the above 
// expression:
//
// $version_id = $major_version * 10000 + $minor_version * 100 + $release_version;
//
// Now with PHP_VERSION_ID we can check for features this PHP version 
// may have, this doesn't require to use version_compare() everytime 
// you check if the current PHP version may not support a feature.
//
// For example, we may here define the PHP_VERSION_* constants thats 
// not available in versions prior to 5.2.7

if (PHP_VERSION_ID < 50207) {
    define('PHP_MAJOR_VERSION',   $version[0]);
    define('PHP_MINOR_VERSION',   $version[1]);
    define('PHP_RELEASE_VERSION', $version[2]);

    // and so on, ...
}
?>

注释

Note:

This information is also available in the predefined constant PHP_VERSION. More versioning information is available using the PHP_VERSION_* constants.

参见

PHP 选项/信息 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: Gets the current PHP version

用户评论:

pavankumar at tutorvista dot com (29-Oct-2010 08:39)

To know, what are the {php} extensions loaded & version of extensions :

<?php
foreach (get_loaded_extensions() as $i => $ext)
{
   echo $ext .' => '. phpversion($ext). '<br/>';
}
?>

Sam Yong - hellclanner at live dot com (28-Aug-2009 05:48)

Take note that if you pass phpversion() with an empty string, eg.

<?php
echo phpversion('');
?>

It will not return anything, since it cannot find an extension with the name string(0) ''.

bitworks at web dot de (26-Jun-2009 03:31)

to realize if the actual version ist newer than '5.2.10'
simply use:

<?php
    if (strnatcmp(phpversion(),'5.2.10') >= 0)
    {
        # equal or newer
    }
    else
    {
        # not sufficiant
    }
?>

dmitry DOT seredinov AT gmail DOT com (10-Jan-2009 09:50)

To simple receive a major PHP version value (e.g., 5.2), you can use next:
<?php
// Output below will looks like '5.2', depends to your version
echo floatval(phpversion());
?>

pl DOT baasch AT skycube DOT net (14-Jul-2008 04:17)

In a addition to phpversion,..

if you've got a system like ubuntu or some else, you get
<?php
echo phpversion(); // 5.2.4-2ubuntu5.2
?>

To fix this, use the following:
<?php
echo substr(phpversion(),0,strpos(phpversion(), '-'));
?>