This implements the Forth part of the socket I/O interface.

The sockets interface is low level, and very close to the
underlying BSD sockets model.

~~~
{{
  'io:Sockets var
  :identify
    @io:Sockets n:zero? [
      #7 io:scan-for dup n:negative?
      [ drop 'IO_DEVICE_TYPE_0004_NOT_FOUND s:put nl ]
      [ !io:Sockets ] choose ] if ;
  ---reveal---
  :io:socket-operation identify @io:Sockets io:invoke ;
}}

:socket:gethostbyname (as-)    #0 io:socket-operation ;
:socket:create        (-n)     #1 io:socket-operation ;
:socket:bind          (sn-n)   #2 io:socket-operation ;
:socket:listen        (nn-nn)  #3 io:socket-operation ;
:socket:accept        (n-nn)   #4 io:socket-operation ;
:socket:connect       (n-nn)   #5 io:socket-operation ;
:socket:send          (sn-nn)  #6 io:socket-operation ;
:socket:recv          (ann-nn) #8 io:socket-operation ;
:socket:close         (n-)     #10 io:socket-operation ;
:socket:configure     (ss-)    #11 io:socket-operation ;
~~~