Checking if a double (or float) is NaN in C++

Question

Is there an isnan() function?

PS.: I\'m in MinGW (if that makes a difference).

I had this solved by using isnan() from , which doe

Answer 1

You can use the isnan() function, but you need to include the C math library.

#include 

As this function is part of C99, it is not available everywhere. If your vendor does not supply the function, you can also define your own variant for compatibility.

inline bool isnan(double x) {
    return x != x;
}