1.\" $NetBSD: byteorder.3,v 1.12 2004/06/10 11:37:35 kleink Exp $ 2.\" 3.\" Copyright (c) 1983, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)byteorder.3 8.1 (Berkeley) 6/4/93 31.\" 32.Dd June 10, 2004 33.Dt BYTEORDER 3 34.Os 35.Sh NAME 36.Nm htonl , 37.Nm htons , 38.Nm ntohl , 39.Nm ntohs 40.Nd convert values between host and network byte order 41.Sh LIBRARY 42.Lb libc 43.Sh SYNOPSIS 44.In arpa/inet.h 45.Ft uint32_t 46.Fn htonl "uint32_t host32" 47.Ft uint16_t 48.Fn htons "uint16_t host16" 49.Ft uint32_t 50.Fn ntohl "uint32_t net32" 51.Ft uint16_t 52.Fn ntohs "uint16_t net16" 53.Sh DESCRIPTION 54These routines convert 16 and 32 bit quantities between network 55byte order and host byte order. 56.Pp 57On machines which have a byte order which is the same as the network 58order, routines are defined as null macros. 59.Pp 60These routines are most often used in conjunction with Internet 61addresses and ports as returned by 62.Xr gethostbyname 3 63and 64.Xr getservent 3 . 65.Sh SEE ALSO 66.Xr gethostbyname 3 , 67.Xr getservent 3 68.Sh STANDARDS 69The 70.Fn htonl , 71.Fn htons , 72.Fn ntohl , 73and 74.Fn ntohs 75functions conform to 76.St -p1003.1-2001 . 77Their use of the fixed-width intger types 78.Fa uint16_t 79and 80.Fa uint32_t 81first appeared in 82.St -xns5 . 83.Sh HISTORY 84The 85.Nm byteorder 86functions appeared in 87.Bx 4.2 . 88.Sh BUGS 89The `l' and `s' suffixes in the names are not meaningful in machines 90where long integers are not 32 bits. 91