FFS(3)			   Linux Programmers Manual		       FFS(3)



NAME
       ffs, ffsl, ffsll - find first bit set in a word

SYNOPSIS
       #include 

       int ffs(int i);

       #define _GNU_SOURCE
       #include 

       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 is, for example, 32 or 64.  The func
       tions 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
       4.3BSD, POSIX.1-2001.

NOTES
       BSD systems have a prototype in .

SEE ALSO
       feature_test_macros(7)

COLOPHON
       This page is part of release 3.05 of the Linux  man-pages  project.   A
       description  of	the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



GNU				  2003-08-05				FFS(3)