From:	<ams AT ludd DOT luth DOT se>
Message-Id:	<200304261506.h3QF6Whp013579@speedy.ludd.luth.se>
Subject:	Re: Yet another try on nan in strto{f,d,ld}
In-Reply-To:	<200304221232.OAA06267@lws256.lu.erisoft.se> "from Martin Stromberg
	at Apr 22, 2003 02:32:06 pm"
To:	djgpp-workers AT delorie DOT com
Date:	Sat, 26 Apr 2003 17:06:32 +0200 (CEST)
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Eli said:
> Btw, is code such as this:
> 
>      double tmp_d = NAN;
> 
> safe when numerical exceptions are unmasked in the FP control word?

I made this program:

#include <float.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>

int
main (void)
{
  double d;

  printf("FPU CW: 0x%08x.\n", _control87(0, 0));
  
  d = NAN;
  printf("d = %.20g.\n", d);

  /* Fault on FPU exception. */
  _control87(0, 0x3f);
  printf("FPU CW: 0x%08x.\n", _control87(0, 0));

  d = NAN;
  printf("d = %.20g.\n", d);

  return(EXIT_SUCCESS);
}

When run, it says:

FPU CW: 0x0000037f.
d = NaN.
FPU CW: 0x00000340.
d = NaN.

I. e. no crash traceback. Does that answer the question?


Right,

						MartinS

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