Turn off display errors using file "php.ini"

In php.ini, comment out:

error_reporting = E_ALL & ~E_NOTICE
error_reporting = E_ALL & ~E_NOTICE | E_STRICT
error_reporting = E_COMPILE_ERROR|E_RECOVERABLE_ERROR|E_ER… _ERROR
error_reporting = E_ALL & ~E_NOTICE

By placing a ; ahead of it (i.e., like ;error_reporting = E_ALL & ~E_NOTICE)

For disabling in a single file, place error_reporting(0); after opening a php tag.

You should consider not displaying your error messages instead!

Set ini_set('display_errors', 'Off'); in your PHP code (or directly into your ini file if possible), and leave error_reporting on E_ALL or whatever kind of messages you would like to find in your logs.

This way you can handle errors later, while your users still don't see them.

Full example:

define('DEBUG', true);
error_reporting(E_ALL);

if (DEBUG)
{
    ini_set('display_errors', 'On');
}
else
{
    ini_set('display_errors', 'Off');
}

Or simply (same effect):

define('DEBUG', true);

error_reporting(E_ALL);
ini_set('display_errors', DEBUG ? 'On' : 'Off');

I always use something like this in a configuration file:

// Toggle this to change the setting
define('DEBUG', true);

// You want all errors to be triggered
error_reporting(E_ALL);

if(DEBUG == true)
{
    // You're developing, so you want all errors to be shown
    display_errors(true);

    // Logging is usually overkill during development
    log_errors(false);
}
else
{
    // You don't want to display errors on a production environment
    display_errors(false);

    // You definitely want to log any occurring
    log_errors(true);
}

This allows easy toggling between debug settings. You can improve this further by checking on which server the code is running (development, test, acceptance, and production) and change your settings accordingly.

Note that no errors will be logged if error_reporting is set to 0, as cleverly remarked by Korri.