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Mail Archives: djgpp/2005/10/21/06:31:23

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From: AndrewC <andspamtrap AT exemail DOT doty DOT com DOT au>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: reading from com1: => driving me nuts
Date: Fri, 21 Oct 2005 20:21:10 +1000
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>> > >What am I doing wrong?
>> > Assuming that you are a embedded C programmer didn't it strike you are
>> > strange that you can't read or write to the uart registers?
>
>> Not at all! If I have a <stdio.h> I prefer using it.
>
>Preferences have nothing to do with it.  <stdio.h> support is simply
>*way* too crude for what you're trying to do.  Remember: this is DOS, not
>UNIX you're programming for, i.e. not everything that could usefully be
>a file actually is.  COM1: is made available as a file, but it's supported
>only on a *very* basic level, by DOS.  You're way beyond the point where
>it makes sense to try and rely on DOS to get things done for you.

From previous posts (not from me) a long time ago if I get this right
(please correct me if I am wrong) the C libs use standard bios calls.

Under DOS only up to and including 9600 are supported and advisable to
work. Any higher and you are asking for trouble on an old PC or a PC
running Windows. Be aware , very aware of this one as I would expect
that you will have problems at some stage running at 115K using the
standard library calls on DOS.

Andrew

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