The error_reporting() is a pre-defined function of PHP. error_reporting in PHP determines what kinds of errors and warnings PHP should report when running a script.
With the help of PHP program specify different levels of error reporting:
<?
// Turn off all error reporting
error_reporting(0);
// Report all PHP errors
error_reporting(E_ALL);
// Report all PHP errors
error_reporting(-1);
// Report all errors except E_NOTICE
error_reporting(E_ALL & ~E_NOTICE);
// Report simple running errors
error_reporting(E_WARNING | E_ERROR | E_PARSE);
// E_NOTICE is also good to report uninitialized variables
error_reporting( E_WARNING |E_ERROR | E_PARSE | E_NOTICE);
// It is same as error_reporting(E_ALL);
ini_set('error_reporting', E_LL);
?>