wp_debug - wordpress debug enable

// Turn debugging on
define('WP_DEBUG', true);

// Tell WordPress to log everything to /wp-content/debug.log
define('WP_DEBUG_LOG', true);

// Turn off the display of error messages on your site
define('WP_DEBUG_DISPLAY', false);

// For good measure, you can also add the follow code, which will hide errors from being displayed on-screen
@ini_set('display_errors', 0);