Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!voder!nsc!amdahl!rtech!ingres!seg
From: seg@ingres.com (scott e garfinkle)
Newsgroups: comp.os.os2.programmer
Subject: Re: VIO, KBD and MOU calls.
Message-ID: <1991Jun12.164928.23952@ingres.Ingres.COM>
Date: 12 Jun 91 16:49:27 GMT
References: <1991Jun11.105427.8068@kingston.ac.uk>
Organization: Ask Computer Systems, Ingres Products Division
Lines: 26

In article <1991Jun11.105427.8068@kingston.ac.uk> cs_b144@ux.kingston.ac.uk (Ian Stickland) writes:
>
>From what I've heard and read about OS/2 2.0 it would appear that 
>the VIO, KBD, and MOU calls have only been kept as 16bit calls.
>this true, and if so WHY?

Up front caveat:  I am not a PM programmer.  If the API doesn't start with
"Dos", I haven't used it.

It really doesn't make any difference that VIO, et al., are only available
as 16-bit calls.  I think that, in general, only calls of a portable nature
were given 32 bit interfaces.  By definition, calls such as VIO are fairly
PC-specific.  In any case, it is pretty easy to write mixed 32/16 bit
interface programs.  There is a new _far16 keyword to facilitate this,
and the Microsoft SDK documentation is unexpectedly lucid in this area.

The only penalty is, of course, that the calls may end up with some extra
address-mapping and segment-loading overhead.  Since you already had the
segment overhead in the 16 bit world, and the address mapping consists
of about two instructions (a SHR and a MOV, as I recall), I can't get too
worked up.

I suspect that, in the long run, you will be better off for speed going
through PM.  I dunno -- I still have no great desire to do user interfaces.

	-scott e. garfinkle