All
The special type "All" is sub-type of all other types. The only value having "All" as type is NULL, which means NULL can be passed for any argument because NULL fits to every type.
NULL always represents an "undefined" value.
The special type "All" is sub-type of all other types. The only value having "All" as type is NULL, which means NULL can be passed for any argument because NULL fits to every type.
NULL always represents an "undefined" value.