The error severity is set to E_ALL on the page, and the error is displayed, but the fatal exception is not reported. why?

The error severity is set to E_ALL on the page, and the error is also displayed, but the fatal error is not reported. why error_reporting (E_ALL); ini_set ('display _ errors ', & nbsp; 'on'); var_dump ($ a) notice errors can be prompted. but the fatal error is not reported directly. to set the error level to E_ALL on the page, the error is also displayed, but the fatal error is not reported. why?

error_reporting(E_ALL);
ini_set('display_errors', 'On');
var_dump($a)

A notice error is prompted.
But the fatal error is not reported. why? (Display_errors = Off in php. ini)
Because my page has an error, this page cannot be executed directly, so

error_reporting(E_ALL);
ini_set('display_errors', 'On');

Cannot be executed? But isn't the code executed from the top down? I don't understand. share it: More