(PHP 4, PHP 5)
dl — Loads a PHP extension at runtime
Loads the PHP extension given by the parameter library.
Use extension_loaded() to test whether a given extension is already available or not. This works on both built-in extensions and dynamically loaded ones (either through php.ini or dl()).
This function has been removed from some SAPI's in PHP 5.3.
This parameter is only the filename of the extension to load which also depends on your platform. For example, the sockets extension (if compiled as a shared module, not the default!) would be called sockets.so on Unix platforms whereas it is called php_sockets.dll on the Windows platform.
The directory where the extension is loaded from depends on your platform:
Windows - If not explicitly set in the php.ini, the extension is loaded from C:\php4\extensions\ (PHP4) or C:\php5\ (PHP5) by default.
Unix - If not explicitly set in the php.ini, the default extension directory depends on
成功时返回 TRUE， 或者在失败时返回 FALSE. If the functionality of loading modules is not available or has been disabled (either by setting enable_dl off or by enabling 安全模式 in php.ini) an E_ERROR is emitted and execution is stopped. If dl() fails because the specified library couldn't be loaded, in addition to FALSE an E_WARNING message is emitted.
Example #1 dl() examples
<?php
// Example loading an extension based on OS
if (!extension_loaded('sqlite')) {
if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
dl('php_sqlite.dll');
} else {
dl('sqlite.so');
}
}
// Or, the PHP_SHLIB_SUFFIX constant is available as of PHP 4.3.0
if (!extension_loaded('sqlite')) {
$prefix = (PHP_SHLIB_SUFFIX === 'dll') ? 'php_' : '';
dl($prefix . 'sqlite.' . PHP_SHLIB_SUFFIX);
}
?>
| 版本 | 说明 |
|---|---|
| 5.3.0 | dl() is now disabled in some SAPI's due to stability issues. The only SAPI's that allow dl() are: CLI, CGI and Embed. Use the Extension Loading Directives instead. |
Note:
dl() is not supported when PHP is built with ZTS support. Use the Extension Loading Directives instead.
Note:
dl() is case sensitive on Unix platforms.
Note: 当 PHP 运行在 安全模式 时，不能使用此函数。