Howard Hinnant wrote:
Do we really want to use gratuitously different names from those in C99:
isfinite isnorm isinf isnan
If we use the C99 names, do we intend on #undef'ing the C99 macros if they exist (C99 says these are macros, not functions)? If we don't then the macros will trash our functions. There's an easy technique for converting the macro (if it exists) into a function (demonstrated by gcc's <cmath>). If we do #undef the C99 macros, this is observable behavior which we should document (lest the client be testing #ifndef isnan after the boost header gets included).
The way I have it set up is to *not* undef anything, that means you have to call them using either: (isnan)(x); or: (boost::math::isnan)(x); Just like we have to do the same thing with min and max already: this usage is documented with examples as well BTW :-)
I recommend restricting these templates to floating point types. Otherwise they are overly generic, and could easily be called accidently, especially isnormal, is_normal, isnorm (or whatever, C99 and C++0X call it isnormal).
Oh, actually I *need* generic versions of these functions in order to make parts of the math toolkit I'm working on generic: at the very least these scale to pretty much anything that has numeric_limits defined, without that all you can do is assume the number is a zero or a normal: but that's OK too because most (all?) extended precision types like NTL::RR don't support infinities or NaN's anyway. Of course passing a complex number or an octonium or something *would* be a mistake, but I'm assuming that any function that makes use of isnan etc wouldn't be compatible with these anyway. John.