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

A possible solution that would not depend on the specific IEEE representation for NaN used would be the following:

template
bool isnan( T f ) {
    T _nan =  (T)0.0/(T)0.0;
    return 0 == memcmp( (void*)&f, (void*)&_nan, sizeof(T) );
}