From:	"Alex Oleynikov" <alex AT compuweigh DOT com>
Newsgroups:	comp.os.msdos.djgpp
References:	<frN89.72711$Pb DOT 3104967 AT news2 DOT east DOT cox DOT net> <7263-Thu22Aug2002105626+0300-eliz AT is DOT elta DOT co DOT il>
Subject:	Re: Problem with tight kbhit() loop
Lines:	38
X-Newsreader:	Microsoft Outlook Express 6.00.2600.0000
X-MimeOLE:	Produced By Microsoft MimeOLE V6.00.2600.0000
Message-ID:	<%z599.106$Or1.19232@news2.east.cox.net>
Date:	Thu, 22 Aug 2002 13:22:03 GMT
NNTP-Posting-Host:	68.15.54.9
X-Complaints-To:	abuse AT cox DOT net
X-Trace:	news2.east.cox.net 1030022523 68.15.54.9 (Thu, 22 Aug 2002 09:22:03 EDT)
NNTP-Posting-Date:	Thu, 22 Aug 2002 09:22:03 EDT
Organization:	Cox Communications
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp
Reply-To:	djgpp AT delorie DOT com

"Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il> wrote in message
news:7263-Thu22Aug2002105626+0300-eliz AT is DOT elta DOT co DOT il...
> > From: "Alex Oleynikov" <alex AT compuweigh DOT com>
> > Newsgroups: comp.os.msdos.djgpp
> >
> > I have a question about using kbhit() function in a tight loop like the
one
> > below:
> > ...
> > while( !kbhit() );
> >
> > ch = getch();
> > ...
> >
> > If I just run the program that contains this code everything works fine.
> > Now, if I run this program under the RHIDE's debugger and have some
> > breakpoints prior to the code listed above, then this loop never quits
and
> > computer locks up completely (only cold re-boot helps to restart it) and
> > sometimes even my CMOS settings are get screwed up, so BIOS loads their
> > default values at start-up making me go nuts restoring them :o).
>
> Is this on plain DOS or on Windows?

No, this is plain DOS.

> If the former, I think it's a known side-effect of the way CWDPMI
> implements the DPMI Interrupt 31 handler: after certain operations
> interrupts are left in disabled state.  Try inserting __asm__("sti")
> inside the loop, and I think the problem will go away.

Yepp, you are right - this takes care of the problem.
Thanks for your help.

Alex

- Raw text -