FMOD

fmod − floating-point remainder function

#include <math.h>

double fmod(double x, double y);

The fmod() function computes the remainder of dividing x by y. The return value is x - n * y, where n is the quotient of x / y, rounded towards zero to an integer.

The fmod() function returns the remainder, unless y is zero, when the function fails and errno is set.

EDOM

The denominator y is zero.

SVID 3, POSIX, BSD 4.3, ISO 9899

drem(3)