error_reporting —You can turn on & turn OFF errors at the run time.

If you set 0: Turn off all PHP error 

// Turn off all error reporting

If you set -1:Report all PHP errors

// Report all PHP errors

E_ALL: Turn on all PHP errors

// Turn on all PHP errors

Suggestion: if your site is in production mode(Live) we will suggest to turn off all PHP error reporting for security purpose.