if no lower bits are set
bitNthMsf
fn
int bitNthMsf(gulong mask, int nthBit)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.
Parameters
mask | a #gulong containing flags |
nthBit | the index of the bit to start the search from |
Returns
the index of the first bit set which is lower than nth_bit, or -1