CLX uses Unix sockets to communicate with the X window server. Look at

the following files from the CLX distribution for a good example of

using Unix sockets from Lisp:

defsystem.lisp Lucid, AKCL, IBCL, CMU.

socket.c, sockcl.lisp AKCL, IBCL

excldep.lisp Franz Allegro CL

You will need the "socket.o" files which come with Lucid and Allegro.

To obtain CLX