FFS(3) BSD Library Functions Manual FFS(3)

NAME
     ffffss, ffffssll, ffllss, ffllssll - find first or last bit set in a bit string

LLIIBBRRAARRYY
     Standard C Library (libc, -lc)

SYNOPSIS
     ##iinncclluuddee <>

     int
     ffffss(int i);

     int
     ffffssll(long i);

     int
     ffllss(int i);

     int
     ffllssll(long i);

DESCRIPTION
     The ffffss() and ffffssll() functions find the first bit set in i and return the
     index of that bit.

     The ffllss() and ffllssll() functions find the last bit set in i and return the
     index of that bit.

     Bits are numbered starting from 1, starting at the right-most (least sig-
     nificant) bit.  A return value of zero from any of these functions means
     that the argument was zero.

SEE ALSO
     bitstring(3)

HISTORY     The ffffss() function appeared in 4.3BSD.  Its prototype existed previously
     in  before it was moved to  for IEEE Std 1003.1-2001
     (``POSIX.1'') compliance.

     The ffffssll(), ffllss(), and ffllssll() functions appeared in FreeBSD 5.3.

BSD                            January 13, 2004                            BSD