... this is the deprecated keyword in the function (method) declaration. If the interpreter meets it, it generates an E_WARNING level error.
Especially sad is the lack of this word because in 5.3 there is even a special level E_USER_DEPRECATED, but there is nothing that could generate such an error, except for the unobvious and inconvenient trigger_error
Just one word, but how much it could change. I really look forward to and believe what will happen.