cpp/numeric/math/fmax

@1-3@ Returns the larger of two floating point arguments, treating NaNs as missing data (between a NaN and a numeric value, the numeric value is chosen). @A@ Additional overloads are provided for all other combinations of arithmetic types.

Return value
If successful, returns the larger of two floating point values. The value returned is exact and does not depend on any rounding modes.

Error handling
This function is not subject to any of the error conditions specified in math_errhandling.

If the implementation supports IEEE floating-point arithmetic (IEC 60559),
 * If one of the two arguments is NaN, the value of the other argument is returned
 * Only if both arguments are NaN, NaN is returned