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[perl #41202] text->float conversion gives wrong answer

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From:
sisyphus@cpan.org via RT
Date:
July 25, 2018 01:55
Subject:
[perl #41202] text->float conversion gives wrong answer
Message ID:
rt-4.0.24-27466-1532483722-1253.41202-15-0@perl.org
On Tue, 24 Jul 2018 15:35:57 -0700, public@khwilliamson.com wrote:

> If you look at the previous smoke report, it's almost all failures.
> 
> http://perl.develop-help.com/?b=smoke-me%2Fjkeenan%2Fsisyphus%2F41202-
> 2nd-text-float

Some of those failures are on quadmath builds, and my patches have no effect on quadmath builds.
All that my numeric.c changes do is to replace "strtoflt128" with "Perl_strtod" (one and the same thing on quadmath builds) and to replace every occurrence of "USE_QUADMATH" with "Perl_strtod" (but "Perl_strtod" is unconditionally defined in perl.h if "USE_QUADMATH" is defined).

From this, I deduce that bugs afflicting quadmath builds cannot be attributable to my alterations to perl.h and numeric.c.
Those alterations could, however, expose "double" and "long double" builds of perl to bugs that previously afflicted only quadmath builds - and I wonder if the lib/locale.t test failures (which I had not seen until a few days ago) might be such a case in point.
I can't reproduce those failures on my Ubuntu-16.04 system, but I see that they occur on both "double" and quadmath builds.

I'll go through the reports there and see if there's anything I should be concerned about.

> James Keenan appears to be afk, so I took your latest patches, and am doing my own smoke.
> You can watch it as the results come in
> 
> http://perl.develop-help.com/?b=smoke-me%2Fkhw-sisyphus

Thanks Karl - I'll peruse them with interest.
So far there's only a couple of Cygwin reports (or the same report twice) that fail to build because of
https://rt.perl.org/Ticket/Display.html?id=133356

Cheers,
Rob




---
via perlbug:  queue: perl5 status: open
https://rt.perl.org/Ticket/Display.html?id=41202

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