Syntax of class_exists
bool class_exists(string name[, bool autoload_class])
Returns true if a class with the same name as the string has been defined; if not, it returns false. The comparison for class names is case-insensitive. If autoload_class is set and is true, the class is loaded through the class’s __autoload() function before getting the interfaces it implements.
Example of class_exists
<?php
// Check that the class exists before trying to use it
if (class_exists('MyClass')) {
$myclass = new MyClass();
}
?>
More Example of class_exists
<?php
spl_autoload_register(function ($class_name) {
include $class_name . '.php';
// Check to see whether the include declared the class
if (!class_exists($class_name, false)) {
throw new LogicException("Unable to load class: $class_name");
}
});
if (class_exists(MyClass::class)) {
$myclass = new MyClass();
}
?>