Hi, I'm trying to compile some image processing software that uses isnan. I'm using gcc 3.3 on os x, so (as was pointed out earlier) the c99 extensions aren't in c++ yet. Thus, when I include on cmath I get a 'isnan' undeclared error. The same goes for when I include both cmath and math.h. When I just include math.h however isnan is defined and I can compile. In compiling this software, I need to somehow figure out how to use both the isnan from math.h and cmath for the other functions defined there in the same header file but not have them conflict. Are there any compiler settings of macros that can be used to do this? thanks, wes