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FFS(3)			    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 signifi-
       cant) 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), bitset(9)

HISTORY
       The ffs() function appeared in 4.3BSD.  Its  prototype  existed	previ-
       ously  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	14.3		       October 17, 2015				FFS(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=ffs&sektion=3&manpath=FreeBSD+14.3-RELEASE+and+Ports>

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