modf function
Implementation
double modf(double x, List<double> iptr) {
if (x.isNaN) {
iptr[0] = double.nan;
return double.nan;
}
if (x.isInfinite) {
iptr[0] = x;
return copysign(0.0, x);
}
iptr[0] = x.truncateToDouble();
return x - iptr[0];
}