Re: Integer division in Lua with numbers as longs

[Reuben Thomas <rrt@...>]

On Tue, 17 Apr 2006, John D. Ramsdell wrote:

> > A user of the patch has suggested to me that Lua's division and
> > modulus operator should satisfy the same equation as C's integer
> > division and remainder operators.
>
> I see this topic was recently discussed in another thread I happened
> not to be following.  I concluded that integer division should work as
> it does in Python, and changed the patch to define division as
> follows.
>
> #define luai_numdiv(a,b) ((a)<0==(b)<0||(a)%(b)==0?(a)/(b):(a)/(b)-1)

This is not reliable: ANSI/ISO C does not specify how integer division 
is rounded (to zero or to -infinity).

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