dl
(PHP 4, PHP 5)
dl — Loads a PHP extension at runtime
说明
bool dl ( string $library )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()).
WarningThis function has been removed from some SAPIs in PHP 5.3.
参数
- library
-
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:php4extensions (PHP 4) or C:php5 (PHP 5) by default.
Unix - If not explicitly set in the php.ini, the default extension directory depends on
- whether PHP has been built with --enable-debug or not
- whether PHP has been built with (experimental) ZTS (Zend Thread Safety) support or not
- the current internal ZEND_MODULE_API_NO (Zend internal module API number, which is basically the date on which a major module API change happened, e.g. 20010901)
返回值
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.
范例
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);
}
?>
更新日志
| 版本 | 说明 |
|---|---|
| 5.3.0 | dl() is now disabled in some SAPIs due to stability issues. The only SAPIs that allow dl() are CLI and Embed. Use the Extension Loading Directives instead. |
注释
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。
参见
- Extension Loading Directives
- extension_loaded() - Find out whether an extension is loaded
