Defined in header <math.h> float fdimf( float x, float y ); (1) (since C99) double fdim( double x, double y ); (2) (since C99) long double fdiml( long double x, long double y ); (3) (since C99) Defined in header <tgmath.h> #define fdim( x, y ) (4) (since C99)
1-3) Returns the positive difference between x and y, that is, if x>y, returns x-y, otherwise (if x≤y), returns +0.
4) Type-generic macro: If any argument has type long do