src/math/fdim.c

   1 #include <math.h>
   2
   3 double fdim(double x, double y)
   4 {
   5         if (isnan(x))
   6                 return x;
   7         if (isnan(y))
   8                 return y;
   9         return x > y ? x - y : 0;
  10 }