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Reply-To: moss@cs.umass.edu
Subject: Re: Floating point exception in strtod()
To: cygwin@cygwin.com
References: <dd5e98ea-8f39-1c4b-116c-37968cb3a52d@cornell.edu>
From: Eliot Moss <moss@cs.umass.edu>
Message-ID: <6e4ccba4-a74b-fb78-db0c-b8d1a2260658@cs.umass.edu>
Date: Sat, 7 Apr 2018 16:56:13 -0400
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On 4/7/2018 1:40 PM, Ken Brown wrote:
> $ cat strtod_test.c
> #include <stdio.h>
> #include <stdlib.h>
> #include <fenv.h>
> 
> int
> main ()
> {
>    /* The following number comes from /usr/share/asymptote/ode.asy.  */
>    const char *str = "121645100408832000.0";
>    char *ptr;
> 
>    feenableexcept (FE_INVALID);
>    strtod (str, &ptr);
> 
>    /* If there was an exception, the following will not get executed.  */
>    printf ("No exception.\n");
> }

If I do the same thing WITHOUT the feenableexcept, it works fine.
Perhaps strtod catches an exception and then applies a different
method in some cases, or perhaps it wants exceptions off and
deals with things its own way.

If I include the feenableexcept, I get the same behavior you
reported (in 32-bit; I did not test 64-bit).

Regards - Eliot Moss

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