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PHP Manual [set_exception_handler]

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PHP Manual || Error Handling Functions

(PHP 5, PHP 7)

set_exception_handler Sets a user-defined exception handler function


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.



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.


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.


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.


Example #1 set_exception_handler() example

function exception_handler($exception) {
"Uncaught exception: " $exception->getMessage(), "\n";


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

See Also

PHP Manual || Error Handling Functions