ffs

FFS(3)                     Linux Programmer's Manual                    FFS(3)



NAME
       ffs - find first bit set in a word

SYNOPSIS
       #include <strings.h>

       int ffs(int i);

       #define _GNU_SOURCE
       #include <string.h>

       int ffsl(long int i);

       int ffsll(long long int i);

DESCRIPTION
       The  ffs()  function  returns the position of the first (least signifi-
       cant) bit set in the word i.  The least significant bit is  position  1
       and  the  most  significant  position  e.g.  32  or 64.   The functions
       ffsll() and ffsl() do the same but take arguments of possibly different
       size.

RETURN VALUE
       These  functions  return  the position of the first bit set, or 0 if no
       bits are set in i.

CONFORMING TO
       BSD 4.3, POSIX 1003.1-2001.

NOTES
       BSD systems have a prototype in <string.h>.



GNU                               2003-08-05                            FFS(3)