C++ header file problem - is this a bug?

[Bill Northcott]

>   As such, you should use the C++ library functions and headers, not 
> the C
> library functions and headers, since they're for a different 
> programming
> language.

Which is nice if you are sitting in an ivory tower, but in the real 
world people need to use C libraries in C++ code and they hit these 
sorts of problems.  That is how we got in trouble.
>
>   Why aren't you using the std::isnan() function?

Thank you that is a helpful suggestion.

Bill Northcott