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`fmod', `fmodf'--floating-point remainder (modulo)

     #include <math.h>
     double fmod(double X, double Y)
     float fmodf(float X, float Y)
The `fmod' and `fmodf' functions compute the floating-point remainder
of X/Y (X modulo Y).
The `fmod' function returns the value X-I*Y, for the largest integer I
such that, if Y is nonzero, the result has the same sign as X and
magnitude less than the magnitude of Y.
   `fmod(X,0)' returns NaN, and sets `errno' to `EDOM'.
   You can modify error treatment for these functions using `matherr'.
`fmod' is ANSI C. `fmodf' is an extension.