1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)byteorder.3 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD$ 30.\" 31.Dd March 20, 2005 32.Dt BYTEORDER 3 33.Os 34.Sh NAME 35.Nm htonl , 36.Nm htons , 37.Nm ntohl , 38.Nm ntohs 39.Nd convert values between host and network byte order 40.Sh LIBRARY 41.Lb libc 42.Sh SYNOPSIS 43.In arpa/inet.h 44.Pp 45or 46.Pp 47.In netinet/in.h 48.Ft uint32_t 49.Fn htonl "uint32_t hostlong" 50.Ft uint16_t 51.Fn htons "uint16_t hostshort" 52.Ft uint32_t 53.Fn ntohl "uint32_t netlong" 54.Ft uint16_t 55.Fn ntohs "uint16_t netshort" 56.Sh DESCRIPTION 57These routines convert 16 and 32 bit quantities between network 58byte order and host byte order. 59On machines which have a byte order which is the same as the network 60order, routines are defined as null macros. 61.Pp 62These routines are most often used in conjunction with Internet 63addresses and ports as returned by 64.Xr gethostbyname 3 65and 66.Xr getservent 3 . 67.Sh SEE ALSO 68.Xr gethostbyname 3 , 69.Xr getservent 3 , 70.Xr byteorder 9 71.Sh STANDARDS 72The 73.Nm byteorder 74functions conform to 75.St -p1003.1-2001 . 76.Sh HISTORY 77The 78.Nm byteorder 79functions appeared in 80.Bx 4.2 . 81.Sh BUGS 82On the 83.Tn VAX 84bytes are handled backwards from most everyone else in 85the world. 86This is not expected to be fixed in the near future. 87