239atomic_list_concat(? As,+ Separator,? A)
stream_property( Stream, Prop )
socket(+ DOMAIN,+ TYPE,+ PROTOCOL,- SOCKET)
maplist( 2:Pred, + List1,+ List2)
hostname_address(? HOSTNAME,? IP_ADDRESS)
socket_accept(+ SOCKET, - STREAM)
socket_accept(+ SOCKET, - CLIENT, - STREAM)
socket_bind(+ SOCKET, ? PORT)
socket_buffering(+ SOCKET, - MODE, - OLD, + NEW)
socket_listen(+ SOCKET, + LENGTH)
socket_select(+ SOCKETS, - NEWSTREAMS, + TIMEOUT, + STREAMS, - READSTREAMS)