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From: erc@pai.UUCP (Eric Johnson)
Newsgroups: comp.windows.x
Subject: Re: what i want in R5
Summary: R4 added new Xlib functions
Message-ID: <1345@pai.UUCP>
Date: 10 Jul 90 15:06:56 GMT
References: <9007070539.AA16621@Larry.McRCIM.McGill.EDU>
Organization: Boulware Technologies, Inc., Burnsville, MN
Lines: 68

In article <9007070539.AA16621@Larry.McRCIM.McGill.EDU>, mouse@LARRY.MCRCIM.MCGILL.EDU (der Mouse) writes:
> > I would like to see the following in the next release of X11:
> 
> > 3. there should be some way to determine which release a particular
> >    vendor's X implementation is based on.
> 
> And if it's not based upon an MIT release, or if it's a blend of more
> than one?
> 
> >    for example, i write a client that must run on a release 4 server.
> 
> What are you doing that depends on the server being an R4 server?  More
> likely you're depending on the existence of a feature which arrived in
> the MIT server with R4, like the SHAPE extension.  You should be
> testing for the presence of the feature rather than for the generic
> release number.  (This is a common problem with software releases,
> particularly with OS features.  People configure "for BSD" or "for SV"
> when what should really be done is is to configure "has/hasn't
> symlinks", "has/hasn't 14-character filename limit", etc; there are
> enough half-breed systems[%] out there that the latter is much more
> useful.)
> 
> [%] Intended as descriptive rather than pejorative.
> 
> 					der Mouse
> 
> 			old: mcgill-vision!mouse
> 			new: mouse@larry.mcrcim.mcgill.edu

I agree in general with your comments about checking for a specific
feature (especially since a great many X terminals out there are
at Release 3+ -- which means something different for each vendor). But...

I need to know, at compile time, whether I'm compiling on an R4 or
R3-based system.  R4 added a number of new Xlib calls, especially
in the window manager interaction area.  Since I want to write
well-behaved X programs, I need to follow the rules.  But, the
rules changed in R4.  What can you do? Look at functions like
like XAllocSizeHints() (which did not exist in R3).  And, do you call
XSetWMNormalHints() or XSetNormalHints() ? It depends.  The hard
part here is that an R4 window manager will expect the extra
data in these hints, while an older one won't. Some of the hints
have no meaning in R4 (or ICCCM 1.0)--they were declared obsolete--
while some hints seem to have a different meaning under R3-based
systems (and w.m.'s).  I you have a really good means of testing for the
presence of an R4 Xlib, please let me know.

This is a tough problem. And, no matter what, you lose (unfortunately).

Another fun problem is the question "what kind of keyboard am I using?"
I know that KeySyms are supposed to make this stuff easy and portable, 
but just take a look at the HP-specific KeySyms on the 9000/300 (with that
awful keyboard) or the Sun Type 4 keyboard (look hard at the keypad,
especially the PageUp/PageDown keys and you'll know what I mean). 

Unfortunately, I don't live in an ideal world. I need to make software
run on various systems and I need to make it run now.  I need to use
the special keys on HP and Sun keyboards and if anyone has a grand
scheme to make this easy, please tell me.

Have fun,
-Eric

-- 
Eric F. Johnson               phone: +1 612 894 0313    BTI: Industrial
Boulware Technologies, Inc.   fax:   +1 612 894 0316    automation systems
415 W. Travelers Trail        email: erc@pai.mn.org     and services
Burnsville, MN 55337 USA