Libc-1439.100.3.tar.gz

[apple/libc.git] / net / byteorder.3

.\" Copyright (c) 1983, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)byteorder.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD: src/lib/libc/net/byteorder.3,v 1.8 2001/10/01 16:08:55 ru Exp $
.\"
.Dd June 4, 1993
.Dt BYTEORDER 3
.Os
.Sh NAME
.Nm htonl ,
.Nm htons ,
.Nm htonll ,
.Nm ntohl ,
.Nm ntohs ,
.Nm ntohll
.Nd convert values between host and network byte order
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In arpa/inet.h
.Ft uint64_t
.Fn htonll "uint64_t hostlonglong"
.Ft uint32_t
.Fn htonl "uint32_t hostlong"
.Ft uint16_t
.Fn htons "uint16_t hostshort"
.Ft uint64_t
.Fn ntohll "uint64_t netlonglong"
.Ft uint32_t
.Fn ntohl "uint32_t netlong"
.Ft uint16_t
.Fn ntohs "uint16_t netshort"
.Sh DESCRIPTION
These routines convert 16 bit, 32 bit, and 64 bit quantities between network
byte order and host byte order.
(Network byte order is big endian, or most significant byte first.)
On machines which have a byte order which is the same as the network
order, routines are defined as null macros.
.Pp
These routines are most often used in conjunction with Internet
addresses and ports as returned by
.Xr gethostbyname 3
and
.Xr getservent 3 .
.Sh SEE ALSO
.Xr gethostbyname 3 ,
.Xr getservent 3
.Sh STANDARDS
The
.Nm byteorder
functions except
.Nm htonll
and
.Nm ntohll
are expected to conform with IEEE Std POSIX.1-200x
.Pq Dq POSIX.1
.Sh HISTORY
The
functions
.Nm htonl,
.Nm htons,
.Nm ntohl,
.Nm ntohs
appeared in
.Bx 4.2 .
.Pp
The functions
.Nm htonll
and
.Nm ntohll
first appeared in OS X 10.10 (Yosemite).
.Sh BUGS
On the
.Tn VAX
bytes are handled backwards from most everyone else in
the world.  This is not expected to be fixed in the near future.