Re: [Mingw-users] bug in strtod()

[Peter R. <pe...@ly...>]

On 2013-12-12 09:41, sis...@op... wrote:
> 
> 
> -----Original Message----- 
> From: Jared Maddox
> 
>>> Absolutely correct - if the problem is with MS, then file a report there.
>>> But the thing I don't understand is how it can be a problem with MS yet 
>>> not
>>> affect the mingw64 compilers that I have running on this same machine.
>>
>> The gcc that you're having problems with is targeting 32-bit, and the
>> one that's fine is targeting 64-bit, right?
> 
> I was thinking that the 32-bit mingw64 compiler (which is fine) is targeting 
> 32-bit.
> If not then that probably explains it.
> 
>> You said that one or another of the Microsoft compilers was producing
>> the same problem, right? If so, then presumably the same copy of the C
>> library is involved in both cases.
> 
> Yes, and I don't doubt that the mingw.org compilers and my MSVC++7.0 
> compiler are using the same copy of the C library - it's just that I 
> *thought* that the 32-bit mingw64 compilers (which produce no discrepancies) 
> would *also* be using the *same* C library.
> If someone can authoritatively tell me that's not so, then it's "puzzle 
> solved" !!
> And if the mingw compilers are bound to this unsatisfactory C library, then 
> I think I'll probably end up migrating to the the 32-bit mingw64 compiler 
> .... which would be rather unfair towards mingw.org, given that it's not 
> their fault.
> 
> I'm not really set up to apply the same testing to the MSVC++ 7.0 compiler 
> but I have tested a number of values for which strtod() rounds incorrectly 
> when using mingw's gcc, and found the same behaviour with MSVC++7.0.
> 
>> The reason (at least if I
>> remember your previous posts correctly) for the error not existing in
>> previous versions of 32-bit gcc ......
> 
> As regards mingw.org compilers, the discrepancies exist on both gcc-3.4.5 
> and gcc-4.7.0. That's the only 2 versions for which I have results.

I think this can only mean that mingw64 has a fixed strtod in its mingwex
library (or would that be mingw64ex?).

Some browsing or their repo [1] also hits at that.

Cheers,
Peter

[1] http://sourceforge.net/apps/trac/mingw-w64/browser/trunk/mingw-w64-crt/gdtoa/README