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Re: [perl #24160] BUG REPORT: INTEGER MATH OCCURRING WHEN NOTEXPECTED

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From:
Dave Mitchell
Date:
January 18, 2013 12:40
Subject:
Re: [perl #24160] BUG REPORT: INTEGER MATH OCCURRING WHEN NOTEXPECTED
Message ID:
20130118124014.GE13982@iabyn.com
On Mon, Jan 14, 2013 at 04:51:39PM -0800, James E Keenan via RT wrote:
> On Sun Oct 07 08:07:13 2012, jkeenan wrote:
> > On Thu Oct 09 13:26:15 2003, nicholas wrote:
> > > On Wed, Oct 08, 2003 at 04:39:31PM -0000, wasquith@red1ast.cr.usgs.gov
> > > (via RT) wrote:
> > > 
> > > > I have stumbled onto strange float/integer/string behavior on
> > > Perl5.8.0 and
> > > > Perl5.8.1 that did not exist in prior Perls.  I have read (see
> > > REFERENCES)
> > > > that Numbers are better behaved in Perl5.8.+ and math is no longer
> > > purely
> > > > floating point.  I am certain that this change has a weakness.
> > > 
> > > This change was motivated by the desire to cope with the increasing
> > > use of 64 bit values in everyday use, such as files >2Gb, 64 bit
> > > device
> > > numbers and nanosecond timings
> > > 
> > > It means that configuring perl to use 64 bit integers doesn't cause
> > > other
> > > parts of arithmetic to go wrong. I'm still digesting your
> > > comprehensive
> > > report, but I don't believe that what you are seeing should be
> > > happening
> > > (hence it would seem that it is a bug in the implementation)
> > > 
> > > 
> > > If you compile perl with the C pre-processor flag
> > > NO_PERL_PRESERVE_IVUV
> > > defined you should get (close to) the 5.6.1 implementation of numeric
> > > operations. This may solve your problems.
> > > 
> > > Meanwhile, I will continue to investigate your report. If possible,
> > > could you also try the modifications that Dave Mitchell suggested?
> > > 
> > > Thanks
> > > 
> > > Nicholas Clark
> > > 
> > 
> > 
> > Nick, Dave:
> > 
> > Can we figure out some disposition for this ticket which has been in the
> > Stalled queue for nine years?

I haven't really got the inclination to wade through that huge report
and test script, although I note that the OP failed to respond to 
either of Nicholas's or my requests for further information.

If anyone can turn the report into something short that looks like it my
be a reproducible bug on a modern perl, I'll have a look at it.

-- 
Diplomacy is telling someone to go to hell in such a way that they'll
look forward to the trip

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