From: Zsban Ambrus <ambrus@...>
Date: 2004-05-06T22:20:46+09:00
Subject: Re: Bug in Float literal (1e-19 == 0) Re: 0.0 sign

On Thu, May 06, 2004 at 07:13:57AM +0900, Tobias Peters wrote:
> What I find much more problematic than 0.0 having a sign is that ruby treats
> 
> 0.0000000000000000001 == 0.0 as true.
> 
> If I've counted correct that should be 1 * 10^-19. Doubles can represent 
> Numbers down to approx. 10^-300.
> 
> 1e-300 == 0.0 is false in ruby, as it should be.
> 
> There must be a bug in the interpreter, where it reads Float literals.
> 
> Tobias

I think this might be a bug in the C library, not ruby.  Don't take this for
sure however.

Why I think this is because something similar seems to occur in Perl too.

I've written a japh "http://www.perlmonks.com/index.pl?node_id=330784".
I've checked that it works on machines with either endianness (linux-ix86
and sun4-solaris-sparc).  However, I've got reports saying that it won't
work on their machine.  One report, 
"http://www.perlmonks.com/index.pl?node_id=331720" looks especially as if
the last few digits of the floating point literals in the code were ignored. 
That last report was on a winnt machine, but it's also said that it doesn't
work on solaris.

Please tell me on what platform and OS did you get the above results.

ambrus