set_exception_handler

(PHP 5, PHP 7)

set_exception_handler — Sets a user-defined exception handler function

Description

set_exception_handler ( callable $exception_handler ) : callable

Sets the default exception handler if an exception is not caught within a try/catch block. Execution will stop after the exception_handler is called.

Parameters

exception_handler

Name of the function to be called when an uncaught exception occurs. This handler function needs to accept one parameter, which will be the exception object that was thrown. This is the handler signature before PHP 7:

handler ( Exception $ex ) : void

Since PHP 7, most errors are reported by throwing Error exceptions, which will be caught by the handler as well. Both Error and Exception implements the Throwable interface. This is the handler signature since PHP 7:

handler ( Throwable $ex ) : void

null may be passed instead, to reset this handler to its default state.

Caution

Note that providing an explicit Exception type hint for the ex parameter in your callback will cause issues with the changed exception hierarchy in PHP 7.

Return Values

Returns the name of the previously defined exception handler, or null on error. If no previous handler was defined, null is also returned.

Changelog

Version	Description
7.0.0	The type of parameter passed into `exception_handler` changed from Exception to Throwable
5.5.0	Previously, if `null` was passed then this function returned `true`. It returns the previous handler since PHP 5.5.0.

Examples

Example #1 set_exception_handler() example

<?php
function exception_handler($exception) {
  echo "Uncaught exception: " , $exception->getMessage(), "\n";
}

set_exception_handler('exception_handler');

throw new Exception('Uncaught Exception');
echo "Not Executed\n";
?>