phpinfo
putenv
PHP Options/Info Functions
PHP Manual

# phpversion

Gets the current PHP version

### Description

string phpversion ([ string `$extension` ] )

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

### Parameters

`extension`

  An optional extension name.

### Return Values

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.

### Examples

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, ...
}
?>`

### Notes

> Note:

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

### See Also

- PHP_VERSION constants
- version_compare
- phpinfo
- phpcredits
- php_logo_guid
- zend_version