On 03/22/15 15:02, Kevin Chan wrote:
Why don't you add an isnan() check? Is there any reason for returning "signbit(num) ? -num : num" instead of returning num?Linux and Windows treats NAN differently and I am not quite sure which I should follow here, so I just leave it for now...
The goal is to make _copysign behave as on windows. The signbit function is not available in Visual Studio.
I think the _copysignf() is supposed to return a (-num) when (num < 0 && sign >0), so I think this "signbit(num) ? -num : num" might be right.
Sorry, I've misread it earlier. This part looks good.
It would be nice to also change signbit definition on systems that doesn't support it, so it at least works for normal numbers.The signbit() function is actually part of C99, not my implementation, so I think it should be supported on most systems? Though I am not quite sure...
It's not available when compiled with Visual Studio. There's following code in math.c: #ifndef signbit #define signbit(x) 0 #endif I think it would be better if it's at least changed to something like: #define signbit(x) ((x)<0 ? 1 : 0) It will not work correctly for -NAN or -0 but it will not break the cases where old implementation was working.
Thanks, Piotr