php man page for set_exception_handler

SET_EXCEPTION_HANDLER(3)						 1						  SET_EXCEPTION_HANDLER(3)

set_exception_handler - Sets a user-defined exception handler function

SYNOPSIS
       callable set_exception_handler (callable  $exception_handler)

DESCRIPTION
	Sets  the  default exception handler if an exception is not caught within a try/catch block. Execution will stop after the $exception_han-
       dler is called.

PARAMETERS
	      o $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:
		void handler (Exception  $ex) 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		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.5.0	|						    |
       |	|						    |
       |	|  Previously, if NULL was passed then	this  func- |
       |	| tion	returned TRUE. It returns the previous han- |
       |	| dler since PHP 5.5.0. 			    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES
       Example #1

	      set_exception_handler(3) example

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

	      set_exception_handler('exception_handler');

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

SEE ALSO
       restore_exception_handler(3), restore_error_handler(3), error_reporting(3), information about the callback type, PHP 5 Exceptions.

PHP Documentation Group 												  SET_EXCEPTION_HANDLER(3)