function bit_nth_msf(mask: Number(gulong), nth_bit: Number(gint)): Number(gint) {
    // Gjs wrapper for g_bit_nth_msf()

Find the position of the first bit set in mask, searching from (but not including) nth_bit downwards. Bits are numbered from 0 (least significant) to sizeof(#gulong) * 8 - 1 (31 or 63, usually). To start searching from the last bit, set nth_bit to -1 or GLIB_SIZEOF_LONG * 8.


a #gulong containing flags


the index of the bit to start the search from


the index of the first bit set which is lower than nth_bit