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From: farren@well.UUCP (Mike Farren)
Newsgroups: net.micro.pc,net.micro.ti
Subject: Re: Help with SWITCHAR
Message-ID: <751@well.UUCP>
Date: Tue, 11-Mar-86 08:51:53 EST
Article-I.D.: well.751
Posted: Tue Mar 11 08:51:53 1986
Date-Received: Fri, 14-Mar-86 04:28:05 EST
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Reply-To: farren@well.UUCP (Mike Farren)
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In article <2279@phri.UUCP> greenber@phri.UUCP (Ross Greenberg) writes:
>
>Well...I suppose it's time to post the Undocumented Interrupt List
>I've had for a while.
>

   Well...if so, it's probably time for me to repeat my warning, given
so many times before, in so many places:

*** THERE'S A REASON THESE ROUTINES ARE UNDOCUMENTED ***

   Especially with PC-DOS (as opposed to MS-DOS), the routines which are
undocumented are so because: 1) They may not be around in the next
iteration of DOS, and therefore may guarantee incompatibility with later
versions.  2) They don't work correctly for general purposes.  A prime
example of this is the "indos" function, which supposedly told you when
it was safe to call DOS functions from interrupt handlers.  Problem is,
it doesn't ALWAYS work, and if a function like this EVER fails, you're 
in deep crud.

   I'm not saying that you should NEVER use undocumented routines, as
sometimes they can let you accomplish things impossible to do without
them.  You should always be aware of the pitfalls, though!

-- 
           Mike Farren
           uucp: {your favorite backbone site}!hplabs!well!farren
           Fido: Sci-Fido, Fidonode 125/84, (415)655-0667