PHP class_exists() function
Description
class_exists() returns true if the specified class is defined.
Syntax
bool class_exists ( string $class_name [, bool $autoload = true ] )Parameters
- class_name - The class name. The name is matched in a case-insensitive manner.
- autoload - Whether or not to call __autoload by default.
Return Values
Returns TRUE if class_name is a defined class, FALSE otherwise.
Example 1
Check that the class exists before trying to use it
<?php//from ww w. j a va 2 s .com
if (class_exists('MyClass')) {
$myclass = new MyClass();
}
?>
Example 2
autoload parameter example
<?php/* w w w. j a v a 2 s .co m*/
function __autoload($class)
{
include($class . '.php');
// Check to see whether the include declared the class
if (!class_exists($class, false)) {
trigger_error("Unable to load class: $class", E_USER_WARNING);
}
}
if (class_exists('MyClass')) {
$myclass = new MyClass();
}
?>