Availability:built-in
user_input and
current_input of the calling thread. Out becomes
user_output and current_output. If Error 
equals
Out an unbuffered stream is associated to the same 
destination and linked to user_error. Otherwise Error 
is used for
user_error. Output buffering for Out is set to
line and buffering on Error is disabled. See 
also prolog/0 
and set_stream/2. 
The clib package provides the library library(prolog_server), 
creating a TCP/IP server for creating an interactive session to Prolog.