If $n is positive, then "$m % $n" is $m minus the largest multiple of $n less than or equal to $m.
....
If the operands $m and $n are floating point values and the absolute value of
$n (that is "abs($n)") is less than "(UV_MAX + 1)", only the integer
portion of $m and $n will be used in the operation (Note: here "UV_MAX"
means the maximum of the unsigned integer type)