1.\" $NetBSD: setbit.9,v 1.3 2012/12/04 18:03:37 christos Exp $ 2.\" 3.\" Copyright (c) 2010 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Jukka Ruohonen. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.Dd December 4, 2012 31.Dt SETBIT 9 32.Os 33.Sh NAME 34.Nm setbit 35.Nd macros related to bitmaps 36.Sh SYNOPSIS 37.In sys/param.h 38.Ft void 39.Fn setbit "array" "x" 40.Ft void 41.Fn clrbit "array" "x" 42.Ft int 43.Fn isset "array" "x" 44.Ft int 45.Fn isclr "array" "x" 46.Sh DESCRIPTION 47The 48.Nm 49family of macros operate with bitmaps, also known as bit arrays. 50.Pp 51In a nutshell, 52.Fn setbit 53sets the bit 54.Fa x 55in 56.Fa array , 57.Fn clrbit 58clears it, 59.Fn isset 60tests whether 61.Fa x 62is set, and 63.Fn isclr 64returns 1 if 65.Fa x 66is not set. 67.Sh EXAMPLES 68The following example declares a buffer of 10 chars, 69treating it as an array of 80 bits: 70.Bd -literal -offset indent 71char buf[10]; 72 73\&... 74 75setbit(buf, 12); /* set the fifth bit in the second byte */ 76.Ed 77.Sh SEE ALSO 78.Xr bitmap 3 , 79.Xr bitstring 3 80.Sh CAVEATS 81The number of valid bits in a given array is assumed to be multiple of 82.Dv CHAR_BIT , 83the number of bits for smallest object that is not a bit-field. 84