pathname-host

(pathname-host pathname)

The host component of a pathname -- always nil here. A rontolisp namestring is a flat, Unix-shaped path with no host syntax, so the component is not present, and nil is what Common Lisp prescribes for a component that is not there.

The argument is still validated as a pathname designator, exactly as namestring validates it, so a non-designator signals rather than answering nil. pathname-device and pathname-version are the two siblings with the same answer for the same reason.

Backend support

All four backends -- one definition in rontolisp source over primitives every backend has.