Re: macro FIXNUM_OVERFLOW_P in lisp.h is valid ?

[Eli Zaretskii]

> Date: Sat, 24 Oct 2009 16:46:55 +0900
> Cc: address@hidden
> From: Toru TSUNEYOSHI <address@hidden>
> 
> >> So in 64-bit platforms, casting `double' to `int' causes lack of
> >> precision already (because a double does not have 64 bits in the
> >> mantissa), doesn't it?
> > 
> > So I make a patch for keep the precision.
> > It tries to deal with the number in type `int' possibly, otherwise it
> > deals with the number in type `double'.
> > 
> > Would you like to check it ?
> 
> I revised the patch.

I think we should fix the make_fixnum_or_float macro, rather than work
around it in C code.

> +#ifdef _LP64
> +       if (v > LONG_MAX / b)

This will probably not portable enough, e.g. on 64-bit Windows.  We
have MOST_POSITIVE_FIXNUM precisely for that reason.