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NAME

       ffs, ffsl, ffsll - 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
       significant) 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 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

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

NOTES

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

SEE ALSO

       memchr(3), feature_test_macros(7)

COLOPHON

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