1.\" $NetBSD: roundup.9,v 1.4 2011/01/24 10:22:15 enami 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 June 8, 2010 31.Dt ROUNDUP 9 32.Os 33.Sh NAME 34.Nm roundup 35.Nd macros for counting and rounding 36.Sh SYNOPSIS 37.In sys/param.h 38.Ft size 39.Fn howmany "x" "size" 40.Ft size 41.Fn roundup "x" "size" 42.Ft size 43.Fn rounddown "x" "size" 44.Ft size 45.Fn roundup2 "x" "size" 46.Ft int 47.Fn powerof2 "x" 48.Sh DESCRIPTION 49The 50.Fn roundup 51and 52.Fn rounddown 53macros return an integer from rounding 54.Fa x 55up and down, respectively, to the next 56.Fa size . 57The 58.Fn howmany 59macro in turn reveals how many times 60.Fa size 61fits into 62.Fa x , 63rounding the residual up. 64.Pp 65The 66.Fn roundup2 67macro also rounds up, but with the assumption that 68.Fa size 69is a power of two. 70If 71.Fa x 72is indeed a power of two, 73.Fn powerof2 74return 1. 75.Sh RETURN VALUES 76The return value is an integer from the respective operation. 77If 78.Fa x 79is 0, all macros except 80.Fn powerof2 81return 0. 82The behavior is undefined if 83.Fa size 84is 0. 85.Sh SEE ALSO 86.Xr ilog2 3 , 87.Xr imax 9 88.Sh CAVEATS 89All described macros make no assumptions about the type of the parameters. 90These are implicitly assumed to be unsigned integers. 91