Sets a user-defined exception handler function
set_exception_handler ( callable $exception_handler ) : callable
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.
Returns the name of the previously defined exception handler, or NULL on error. If no previous handler was defined, NULL is also returned.
Uncaught Exception: Exception