Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!bloom-beacon!think!ames!sdcsvax!ucbvax!SUN.COM!dshr
From: dshr@SUN.COM (David Rosenthal)
Newsgroups: comp.windows.x
Subject: window manager property semantics
Message-ID: <8710122038.AA00363@devnull.sun.com>
Date: Mon, 12-Oct-87 14:15:58 EDT
Article-I.D.: devnull.8710122038.AA00363
Posted: Mon Oct 12 14:15:58 1987
Date-Received: Wed, 14-Oct-87 02:09:52 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 34

I strongly support Adam's note deprecating the use of properties as
commands to the window manager to map and resize windows.  The clinching
argument (which Adam omitted) is that the use of properties in this way
assumes infinitely reliable window managers.  The use of a command-line
argument,  or a property on the root window,  as a way of finding out
if a window manager is running,  is obviously bogus;  it tells you either
that the user thinks that a window manager is running,  or that a window
manager once ran.  The way to do it is to examine the all-event-masks
field returned by GetWindowAttributes.  But using this means an extra
round-trip on every window manipulation,  and STILL leaves you with a
window of vulnerability in which the window manager can vanish,  and
the application will do the wrong thing:

	GetWindowAttributes(&foo)	/*Start Window of vulnerability */
	if (foo.all_event_mask & (SubstructureRedirect|CreateNotify|...) {
		/*Window manager is running */
		ChangeProperty()
	} else {
		/*No window manager*/
		MapWindow()
	}
	/* End window of vulnerability */

Making all window manipulations look like this would be really intolerable.

As I see it,  the ONLY case in which an application should not explicitly
size & map its window is the case of an application that wants to start
iconinc,  but does not have an icon window.  The behaviour of iconic things
that don't have a window is entirely up to the window manager,  but I don't regard
this as an argument for the application not sizing & mapping,  it is rather
an argument that if the application really wants to start iconic,  it had better
have an icon window (and size and map it ......).

	David.