Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!ukc!tcdcs!nixeid!keogh
From: keogh@nixeid.UUCP (Paul Keogh)
Newsgroups: comp.windows.ms.programmer
Subject: Out of Control - how to master the queue ?
Keywords: DDE, GetMessage, IPC
Message-ID: <60@nixeid.UUCP>
Date: 13 Dec 90 14:08:39 GMT
Organization: Nixdorf Computer Software,Dublin Ireland
Lines: 31

I want to use Windows DDE for simulating Unix System V IPC and have run into
the following problem:

I open an "invisible" Window which manages the application defined messages.
When I send a message to the "invisible" Window, I want that message to stay
on the queue until I call

	GetMessage (&MSG, InvisbleWindow, WM_USER, WM_USER)

ie. I want to retrieve only messages of the WM_USER type. My problem is that
I cannot see way of maintaining the messages on the queue because the Window
procedure defined in the Window Class structure is called to process the
incoming message - defining the procedure as NULL obiviously won't work, nor
will making the Window procedure re-submit the message as the architecture is
re-entrant. 

I can work around this by abstracting the IPC to a higher level - storing
the messages in my defined queues and managing them myself. I would prefer to
use the Windows mechanisms to avoid the overhead involved in that.

The reason I am using my own messages rather than WM_DDE_XXX is that you must
use different *types* of messages for data interchange between client/server  
and server/client under DDE. Any messaging system that requires this is IMHO,
fundamentally flawed.

-- 
Paul Keogh, 			*  People said we couldn't play
SNI Software Center Ireland  	*  That we were only foul mouth yobs
Dublin, Ireland.		*  But the only notes that really count
				*  Are the ones that come in wads
Net: keogh@u.nix.ie		*