nth_lsf

Find the position of the first bit set in mask, searching from (but not including) nth_bit upwards.

Bits are numbered from 0 (least significant) to sizeof(ulong) * 8 - 1 (31 or 63, usually). To start searching from the 0th bit, set nth_bit to -1.

Parameters:

mask	a ulong containing flags
nth_bit	the index of the bit to start the search from

Returns:

the index of the first bit set which is higher than nth_bit, or -1 if no higher bits are set