The set_exception_handler Function

The set_exception_handler function allows you to define a function that will be called to handle uncaught exceptions. It takes either the name of the handler function or an anonymous function as a parameter. The handler receives the exception object as its parameter.

Syntax

set_exception_handler(callable $exception_handler): callable

Example

Let's set a simple exception handler:

<?php
	function myExceptionHandler($exception) {
		echo 'Caught exception: ' . $exception->getMessage();
	}
	
	set_exception_handler('myExceptionHandler');
	
	throw new Exception('Something went wrong!');
?>

Code execution result:

'Caught exception: Something went wrong!'

Example

Using an anonymous function as a handler:

<?php
	set_exception_handler(function($exception) {
		echo 'Error: ' . $exception->getMessage();
	});
	
	throw new Exception('Critical error');
?>

Code execution result:

'Error: Critical error'

Example

Restoring the previous handler:

<?php
	function firstHandler($exception) {
		echo 'First handler: ' . $exception->getMessage();
	}
	
	function secondHandler($exception) {
		echo 'Second handler: ' . $exception->getMessage();
	}
	
	set_exception_handler('firstHandler');
	$old_handler = set_exception_handler('secondHandler');
	restore_exception_handler(); // Restores firstHandler
	
	throw new Exception('Test');
?>

Code execution result:

'First handler: Test'