PHP constants don’t have the leading $. Strictly, this isn’t WordPress, but since there isn’t a Core is_debug() function that I am aware of, what you want is: if (defined(‘WP_DEBUG’) && true === WP_DEBUG) { echo ‘d00d’; }
When WP_DEBUG is set, WordPress sets (via wp_debug_mode() call early in core load process) the error reporting level to E_ALL & ~E_DEPRECATED & ~E_STRICT. This means all warnings and errors except strict errors and PHP deprecated functions (not WordPress ones). You can define your own level in a custom mu-plugin (the override needs to be … Read more
WP_DEBUG has no impact on PHP error output. In addition to error_reporting setting, set display_errors=0 in your php.ini file. It’s enabled by default for development. But you’ll want it off on production servers.
I don’t think there is a universal URL hook. There are a lot of hooks and I may have missed it, but I don’t think there is one. You can look through the hooks at adambrown.info. There are a lot of URL hooks, but not a universal one. If I may suggest another solution: Log … Read more