usocket:host-to-hostname usocket:get-host-by-name

(usocket:host-to-hostname host) -- (usocket:get-host-by-name name)

The usocket host-designator pair. host-to-hostname renders any designator upstream accepts as a hostname/dotted-quad string: nil is the wildcard host "0.0.0.0", a string passes through, a vector quad (or list of four octets) and a host-byte-order 32-bit integer become the dotted quad.

get-host-by-name is lite: rontolisp has no name-resolution primitive on any backend, so it renders its argument through host-to-hostname instead of resolving it to upstream's vector quad. That keeps the normalize-then-hand-on chain libraries use -- (usocket:host-to-hostname (usocket:get-host-by-name address)) -- an identity on the address it is given, and the usocket:socket-connect / usocket:socket-listen call that address reaches still resolves it for real (natively on the interpreter and the JVM; IPv4 literals only on WASM).

Backend support

Works on all four backends, and answers identically on each: both are pure Lisp in the shim and neither opens a socket, so unlike the rest of the usocket API they are available on WASM Preview 1 too.