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FFS(3)		       FreeBSD Library Functions Manual			FFS(3)

NAME
     ffs, ffsl,	ffsll, fls, flsl, flsll	-- find	first or last bit set in a bit
     string

LIBRARY
     Standard C	Library	(libc, -lc)

SYNOPSIS
     #include <strings.h>

     int
     ffs(int value);

     int
     ffsl(long value);

     int
     ffsll(long	long value);

     int
     fls(int value);

     int
     flsl(long value);

     int
     flsll(long	long value);

DESCRIPTION
     The ffs(),	ffsl() and ffsll() functions find the first (least signifi-
     cant) bit set in value and	return the index of that bit.

     The fls(),	flsl() and flsll() functions find the last (most significant)
     bit set in	value and return the index of that bit.

     Bits are numbered starting	at 1, the least	significant bit.  A return
     value of zero from	any of these functions means that the argument was
     zero.

SEE ALSO
     bitstring(3)

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

     The ffsl(), fls() and flsl() functions appeared in	FreeBSD	5.3.  The
     ffsll() and flsll() functions appeared in FreeBSD 7.1.

FreeBSD	10.1		      September	29, 2012		  FreeBSD 10.1

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | SEE ALSO | HISTORY

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<http://www.freebsd.org/cgi/man.cgi?query=ffs&manpath=FreeBSD+10.1-RELEASE>

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