1*2fe8fb19SBen Gras.\" Copyright (c) 1990, 1991, 1993 2*2fe8fb19SBen Gras.\" The Regents of the University of California. All rights reserved. 3*2fe8fb19SBen Gras.\" 4*2fe8fb19SBen Gras.\" This code is derived from software contributed to Berkeley by 5*2fe8fb19SBen Gras.\" Chris Torek. 6*2fe8fb19SBen Gras.\" Redistribution and use in source and binary forms, with or without 7*2fe8fb19SBen Gras.\" modification, are permitted provided that the following conditions 8*2fe8fb19SBen Gras.\" are met: 9*2fe8fb19SBen Gras.\" 1. Redistributions of source code must retain the above copyright 10*2fe8fb19SBen Gras.\" notice, this list of conditions and the following disclaimer. 11*2fe8fb19SBen Gras.\" 2. Redistributions in binary form must reproduce the above copyright 12*2fe8fb19SBen Gras.\" notice, this list of conditions and the following disclaimer in the 13*2fe8fb19SBen Gras.\" documentation and/or other materials provided with the distribution. 14*2fe8fb19SBen Gras.\" 3. Neither the name of the University nor the names of its contributors 15*2fe8fb19SBen Gras.\" may be used to endorse or promote products derived from this software 16*2fe8fb19SBen Gras.\" without specific prior written permission. 17*2fe8fb19SBen Gras.\" 18*2fe8fb19SBen Gras.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19*2fe8fb19SBen Gras.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20*2fe8fb19SBen Gras.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21*2fe8fb19SBen Gras.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22*2fe8fb19SBen Gras.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23*2fe8fb19SBen Gras.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24*2fe8fb19SBen Gras.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25*2fe8fb19SBen Gras.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26*2fe8fb19SBen Gras.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27*2fe8fb19SBen Gras.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28*2fe8fb19SBen Gras.\" SUCH DAMAGE. 29*2fe8fb19SBen Gras.\" 30*2fe8fb19SBen Gras.\" from: @(#)ffs.3 8.2 (Berkeley) 4/19/94 31*2fe8fb19SBen Gras.\" $NetBSD: ffs.3,v 1.13 2010/04/28 07:47:09 jruoho Exp $ 32*2fe8fb19SBen Gras.\" 33*2fe8fb19SBen Gras.Dd April 28, 2010 34*2fe8fb19SBen Gras.Dt FFS 3 35*2fe8fb19SBen Gras.Os 36*2fe8fb19SBen Gras.Sh NAME 37*2fe8fb19SBen Gras.Nm ffs 38*2fe8fb19SBen Gras.Nd find first bit set in a bit string 39*2fe8fb19SBen Gras.Sh LIBRARY 40*2fe8fb19SBen Gras.Lb libc 41*2fe8fb19SBen Gras.Sh SYNOPSIS 42*2fe8fb19SBen Gras.In strings.h 43*2fe8fb19SBen Gras.Ft int 44*2fe8fb19SBen Gras.Fn ffs "int value" 45*2fe8fb19SBen Gras.Sh DESCRIPTION 46*2fe8fb19SBen GrasThe 47*2fe8fb19SBen Gras.Fn ffs 48*2fe8fb19SBen Grasfunction finds the first bit set in 49*2fe8fb19SBen Gras.Fa value 50*2fe8fb19SBen Grasand returns the index of that bit. 51*2fe8fb19SBen GrasBits are numbered starting from 1, starting at the right-most 52*2fe8fb19SBen Grasbit. 53*2fe8fb19SBen GrasA return value of 0 means that the argument was zero. 54*2fe8fb19SBen Gras.Sh SEE ALSO 55*2fe8fb19SBen Gras.Xr bitstring 3 , 56*2fe8fb19SBen Gras.Xr ffs32 3 , 57*2fe8fb19SBen Gras.Xr popcount 3 58*2fe8fb19SBen Gras.Sh STANDARDS 59*2fe8fb19SBen GrasThe 60*2fe8fb19SBen Gras.Fn ffs 61*2fe8fb19SBen Grasfunction conforms to 62*2fe8fb19SBen Gras.St -p1003.1-2001 . 63*2fe8fb19SBen Gras.Sh HISTORY 64*2fe8fb19SBen GrasThe 65*2fe8fb19SBen Gras.Fn ffs 66*2fe8fb19SBen Grasfunction appeared in 67*2fe8fb19SBen Gras.Bx 4.3 . 68*2fe8fb19SBen GrasThe prototype for it existed previously in the 69*2fe8fb19SBen Gras.In string.h 70*2fe8fb19SBen Grasheader before it was moved to 71*2fe8fb19SBen Gras.In strings.h 72*2fe8fb19SBen Grasfor 73*2fe8fb19SBen Gras.Tn POSIX 74*2fe8fb19SBen Grascompliance. 75