--- a/lisp/code-process.el	Mon Aug 13 11:25:03 2007 +0200
+++ b/lisp/code-process.el	Mon Aug 13 11:26:11 2007 +0200
@@ -198,9 +198,9 @@
 
 See also the function `find-operation-coding-system'.")
 
-(defun open-network-stream (name buffer host service)
+(defun open-network-stream (name buffer host service &optional protocol)
   "Open a TCP connection for a service to a host.
-Returns a subprocess-object to represent the connection.
+Return a subprocess-object to represent the connection.
 Input and output work as for subprocesses; `delete-process' closes it.
 Args are NAME BUFFER HOST SERVICE.
 NAME is name for process.  It is modified if necessary to make it unique.
@@ -211,7 +211,17 @@
  with any buffer
 Third arg is name of the host to connect to, or its IP address.
 Fourth arg SERVICE is name of the service desired, or an integer
- specifying a port number to connect to."
+ specifying a port number to connect to.
+Fifth argument PROTOCOL is a network protocol.  Currently 'tcp
+ (Transmission Control Protocol) and 'udp (User Datagram Protocol) are
+ supported.  When omitted, 'tcp is assumed.
+
+Ouput via `process-send-string' and input via buffer or filter (see
+`set-process-filter') are stream-oriented.  That means UDP datagrams are
+not guaranteed to be sent and received in discrete packets. (But small
+datagrams around 500 bytes that are not truncated by `process-send-string'
+are usually fine.)  Note further that UDP protocol does not guard against 
+lost packets."
   (let (cs-r cs-w)
     (let (ret)
       (catch 'found
@@ -245,6 +255,6 @@
 	   (or coding-system-for-read cs-r))
 	  (coding-system-for-write
 	   (or coding-system-for-write cs-w)))
-      (open-network-stream-internal name buffer host service))))
+      (open-network-stream-internal name buffer host service protocol))))
 
 ;;; mule-process.el ends here