text: FMOD(3) BSD Programmer's Manual FMOD(3)
  fmod, fmodf - floating-point remainder function
  libm
  #include <math.h> double fmod(double x, double y); float fmodf(float x, float y);
  The fmod() function computes the floating-point remainder of x/ y.
  The fmod() and fmodf() functions return the value x-i*y, for some integer i such that, if y is non-zero, the result has the same sign as x and mag- nitude less than the magnitude of y. If y is zero, whether a domain error occurs or the fmod() function returns zero is implementation-defined.
  math(3)
  The fmod() function conforms to ANSI X3.159-1989 ("ANSI C"). MirOS BSD #10-current May 2,.