Description
int
dl ( string library )
Loads the PHP extension given by the parameter
library. The library
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.
Returns TRUE on success or FALSE on failure. If the functionality of loading modules is not available
(see Note) or has been disabled (either by turning it off
enable_dl or by enabling safe mode
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.
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()).
The dl() function is deprecated as of PHP 5.
Use Extension Loading Directives
method instead.
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);
}
?>
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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\ 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)
Taking into account the above, the directory then defaults to
<install-dir>/lib/php/extensions/ <debug-or-not>-<zts-or-not>-ZEND_MODULE_API_NO,
e.g.
/usr/local/php/lib/php/extensions/debug-non-zts-20010901
or
/usr/local/php/lib/php/extensions/no-debug-zts-20010901.
Note:
dl() is not supported in
multithreaded Web servers. Use the extensions
statement in your php.ini when operating under such
an environment. However, the CGI and
CLI build are not
affected !
Note:
dl() is case sensitive on Unix platforms.
Note: This function is disabled in safe mode.
See also
Extension Loading Directives
and extension_loaded().
