ffs

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 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
       ffs():4.3BSD,POSIX.1-2001.  The ffsl() and  ffsll()  are  glibc  exten-
       sions.

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

SEE ALSO
       memchr(3), feature_test_macros(7)

COLOPHON
       This  page  is  part of release 3.23 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                               2009-08-27                            FFS(3)