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Re: strtod [was: M4 1.4.14 on AIX 7.1BETA]
From: |
Eric Blake |
Subject: |
Re: strtod [was: M4 1.4.14 on AIX 7.1BETA] |
Date: |
Thu, 29 Jul 2010 08:38:39 -0600 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.7) Gecko/20100720 Fedora/3.1.1-1.fc13 Lightning/1.0b2pre Mnenhy/0.8.3 Thunderbird/3.1.1 |
On 07/29/2010 08:33 AM, Rainer Tammer wrote:
>> ASSERT (result == 10.0);
>>
>> Weird - I've never seen that line fail before. If you have a debugger,
>> can you put a breakpoint on that line and print the actual value of
>> result?
> I can do that.
>
> main(), line 234 in "test-strtod.c"
>
> (dbx) print result
> 10.000000000000002
Yep - rounding inaccuracies have crept in, even for something as simple
as 1 * pow(10,1). Which gives me hope that latest gnulib will be
immune, since we ditched pow(). But it also makes me wonder who's at
fault for introducing a rounding error on such a seemingly simple
operation - hardware, compiler, or former gnulib algorithm?
--
Eric Blake address@hidden +1-801-349-2682
Libvirt virtualization library http://libvirt.org
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- Re: M4 1.4.14 on AIX 7.1BETA, Eric Blake, 2010/07/29
- Re: M4 1.4.14 on AIX 7.1BETA, Rainer Tammer, 2010/07/29
- strtod [was: M4 1.4.14 on AIX 7.1BETA], Eric Blake, 2010/07/29
- [PATCH] strtod: aid debugging, Eric Blake, 2010/07/29
- Re: strtod [was: M4 1.4.14 on AIX 7.1BETA], Rainer Tammer, 2010/07/29
- Re: strtod [was: M4 1.4.14 on AIX 7.1BETA],
Eric Blake <=
- Re: strtod [was: M4 1.4.14 on AIX 7.1BETA], Eric Blake, 2010/07/29
- Message not available
- Message not available
- Message not available
- Re: strtod [was: M4 1.4.14 on AIX 7.1BETA], Eric Blake, 2010/07/29
- Message not available
- Re: strtod [was: M4 1.4.14 on AIX 7.1BETA], Eric Blake, 2010/07/29
- [PATCH] strtod: fix replacement bug on AIX., Eric Blake, 2010/07/29
- Re: strtod [was: M4 1.4.14 on AIX 7.1BETA], Rainer Tammer, 2010/07/30
- Re: strtod [was: M4 1.4.14 on AIX 7.1BETA], Eric Blake, 2010/07/30
- Re: strtod [was: M4 1.4.14 on AIX 7.1BETA], Rainer Tammer, 2010/07/30
- Message not available
- Re: c-stack [was: M4 1.4.14 on AIX 7.1BETA], Eric Blake, 2010/07/29
- Re: c-stack [was: M4 1.4.14 on AIX 7.1BETA], Eric Blake, 2010/07/29
- Message not available
- Re: regex [was: M4 1.4.14 on AIX 7.1BETA], Eric Blake, 2010/07/29