fdim, fdimf, fdiml - compute positive difference

Syntax	#include <math.h> C11 double fdim(double x, double y); float fdimf(float x, float y); long double fdiml(long double x, long double y); (End)
Description	These functions compute the positive difference between the floating-point numbers x and y.
Return val.	x - y                   if x > y, f successful 0                        if x <= y, f successful HUGE_VAL/HUGE_VALF/HUGE_VALL                           depending on the function type, if an overflow occurs.                           errno is set to indicate the error.
Errors	fdim(), fdimf() and fdiml() will fail if: ERANGE            Overflow; the return value is too high.
See also	fmax(), fmin(), math.h.