extension_loaded

Description

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

Example 1. extension_loaded() example <?php if (!extension_loaded('gd')) { if (!dl('gd.so')) { exit; } } ?>

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]

See also get_loaded_extensions(), get_extension_funcs(), phpinfo(), and dl().