From:	Thomas Demmer <demmer AT LSTM DOT Ruhr-UNI-Bochum DOT De>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Error Trapping -- How??
Date:	Thu, 05 Mar 1998 08:33:16 +0100
Organization:	Lehrstuhl fuer Stroemungsmechanik
Lines:	53
Message-ID:	<34FE553C.B9113BD4@LSTM.Ruhr-UNI-Bochum.De>
References:	<34FE22ED DOT 6BCF0CCE AT concentric DOT net>
NNTP-Posting-Host:	bvb.lstm.ruhr-uni-bochum.de
Mime-Version:	1.0
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

D. Huizenga wrote:
> 
> Hi.
> 
> I have a realativly simple question: is it possible to trap errors in
> DJGPP after they occur?  What I mean is if something like an FPE occurs,
> is it possible to have DJGPP run a function which attempts to correct
> the problem?  This is probably a really stupid question, but thanks for
> your help.
Yes, you can.

volatile int merr=0;
static unsigned int fpcw;
void math_handler(int sig){
   fpcw = _clear87() & 0xff;
   printf("SIGFPE: %x\n",fpcw);
   merr = fpcw;
}

int main(int argc, char **argv){
double foo,bar;   
  signal(SIGFPE,math_handler);
  foo=0.; bar = 1.;
  bar = bar/foo;
  return 0;
}

You also may want to include <libm/math.h>,
say  
 _fdlib_version = _SVID_;
 _control87(EM_UNDERFLOW, ~EM_UNDERFLOW);
 _control87(EM_INEXACT, ~EM_INEXACT);

and define your own
int matherr(struct exception *e)

to correct errors...
  

-- 
Ciao
Tom

*************************************************************
* Thomas Demmer                                             *
* Lehrstuhl fuer Stroemungsmechanik                         *
* Ruhr-Uni-Bochum                                           *
* Universitaetsstr. 150                                     *
* D-44780  Bochum                                           *
* Tel: +49 234 700 6434                                     *
* Fax: +49 234 709 4162                                     *
* http://www.lstm.ruhr-uni-bochum.de/~demmer                *
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