cc [flag ...] file ... -lm [library ...]
double remainder(double x, double y);
float remainderf(float x, float y);
long double remainderl(long double x, long double y);
double remquo(double x, double y, int *quo);
float remquof(float x, float y, int *quo);
long double remquol(long double x, long double y, int *quo);
remquo, remquof and remquol return the floating point remainder of the division of x by y. In the object pointed to by quo they store a value whose sign is the sign of x/y and whose magnitude is congruent modulo 2^n to the magnitude of the integral quotient of x/y, where n is an implementation-defined integer greater than or equal to 3.
If x is ± and y is is not a NaN remainder and remquo (and their floating and long double equivalents) return a NaN, raise an invalid operation exception and set errno to EDOM.
On systems that support IEEE NaN, if the argument to any of these functions is a quiet NaN, that value is returned. If the argument is a signaling NaN, a quiet NaN is returned and the invalid operation exception is raised. In either case, errno is set to EDOM.