dl
Loads a PHP extension at runtime
Description
bool dl(string $extension_filename
)
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).
Warning
This function is only available for the CLI and embed SAPIs,
and the CGI SAPI when run from the command line.
Parameters
-
extension_filename
-
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:\php5\ 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 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.
Return Values
Returns true
on success or false
on failure. If the functionality of loading modules is not available
or has been disabled (by setting
enable_dl off
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.
Examples
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 using PHP_SHLIB_SUFFIX constant
if (!extension_loaded('sqlite')) {
$prefix = (PHP_SHLIB_SUFFIX === 'dll') ? 'php_' : '';
dl($prefix . 'sqlite.' . PHP_SHLIB_SUFFIX);
}
?>
Notes
Note:
dl is case sensitive on Unix platforms.