I agree. I would probably use a macro:
#define LCMS_EQ(a,b) (fabs((double)(a) - (double)(b)) <= DBL_EPSILON)
if (LCMS_EQ(xyz->X, 0) && LCMS_EQ(xyz->Y, 0) && LCMS_EQ(xyz->Z, 0))
{ ... }
if (LCMS_EQ(L, 0.0)) { ... }
or, if the test is always against 0:
#define LCMS_EQ_ZERO(a) (fabs((double(a)) <= DBL_EPSILON)
If (LCMS_EQ_ZERO(xyz->X) &&
LCMS_EQ_ZERO(xyz->Y) &&
LCMS_EQ_ZERO(xyz->Z))
{ ... }
if (LCMS_EQ_ZERO(L) { ... }
Glenn
On Sat, Oct 17, 2009 at 1:39 AM, Ethan Hansen <ehan...@drycreekphoto.com> wrote:
> Several of the conversion routines in cmspcs.c perform explicit comparisons
> of double values to 0. Depending on the compiler used and the optimization
> parameters, these comparisons can be unreliable. A floating point number may
> not be *exactly* 0 - or any other specific number for that matter - although
> that was the intent of the program and/or programmer.
>
>
>
> Suggested changes:
>
> 26a27,28
>> #include <float.h>
>>
>
> 183c185
> < if (xyz -> X == 0 && xyz -> Y == 0 && xyz -> Z == 0)
> ---
>> if (fabs(xyz -> X) <= DBL_EPSILON && fabs(xyz -> Y) <= DBL_EPSILON
> && fabs(xyz -> Z) <= DBL_EPSILON)
>
> 296c298
> < if (L==0.0) {
> ---
>> if (fabs(L) <= DBL_EPSILON) {
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