Re: better float2str() C code, anyone?
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- Subject: Re: better float2str() C code, anyone?
- From: Luiz Henrique de Figueiredo <lhf@...>
- Date: Wed, 1 Dec 2004 12:54:17 -0200
> One issue I've had from time to time is that the default
> #define LUA_NUMBER_FMT "%.14g"
> is not long enough to do reversible conversions on doubles. I believe
> you need %.19g for the conversion to be reversible.
I think it's %.17g for IEEE doubles. (Despite what DBL_DIG says!)
Lua was like that once, but then you get ugly things like this:
> =string.format("%.17g",0.34)
0.34000000000000002
> =0.34
0.34
> =34/100
0.34
Users complaint that this is an error in Lua! And it does not help to point
them to docs like http://lua-users.org/wiki/FloatingPoint ...
--lhf