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Date: Wed, 19 Dec 2012 09:30:54 +0800
From: KHMan <keinhong AT gmail DOT com>
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Subject: Re: Bug in Cygwin strtod()
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On 12/19/2012 8:54 AM, Cary R. wrote:
> The following code demonstrates a subtle bug in the Cygwin version of strtod(). The value it generates is slightly different than the value when using the math header files. This used to work correctly some time ago (months). I just took the time to track the problem down in our regression suite.
>
> #include<math.h>
> #include<stdio.h>
> #include<stdlib.h>
>
> int main()
> {
>      double value = M_LN10;
>
>      printf("generate const. - value: %0.15f.\n", value);
>      printf("expected const. - value: 2.302585092994046.\n");
>
>      printf("\n");
>      value = strtod("2.30258509299404568402", 0);
>
>      /* Note: the last digit is incorrect. */
>      printf("generate strtod - value: %0.15f.\n", value);
>      printf("expected strtod - value: 2.302585092994046.\n");
>
>      return 0;
> }

Yep, looks like the significand misses its mark by 1.

-- 
Cheers,
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia

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