extension_loaded

(PHP 4, PHP 5)

extension_loaded — Find out whether an extension is loaded

说明

bool extension_loaded ( string $name )

Finds out whether the extension is loaded.

参数

name

The extension name.

You can see the names of various extensions by using phpinfo() or if you're using the CGI or CLI version of PHP you can use the -m switch to list all available extensions:

$ php -m
[PHP Modules]
xml
tokenizer
standard
sockets
session
posix
pcre
overload
mysql
mbstring
ctype

[Zend Modules]

返回值

Returns TRUE if the extension identified by name is loaded, FALSE otherwise.

范例

Example #1 extension_loaded() example


<?php
if (!extension_loaded('gd')) {
    if (!dl('gd.so')) {
        exit;
    }
}
?>

更新日志

版本	说明
5.0.0	extension_loaded() uses the internal extension name to test whether a certain extension is available or not. Most internal extension names are written in lower case but there may be extensions available which also use uppercase letters. Prior to PHP 5, this function compared the names case sensitively.

参见

get_loaded_extensions() - Returns an array with the names of all modules compiled and loaded
get_extension_funcs() - Returns an array with the names of the functions of a module
phpinfo() - Outputs information about PHP's configuration
dl() - Loads a PHP extension at runtime
function_exists() - Return TRUE if the given function has been defined