NetBSD/lib/libc/net/byteorder.3

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.\" $NetBSD: byteorder.3,v 1.14 2006/02/04 22:47:28 uwe Exp $
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.\" @(#)byteorder.3 8.1 (Berkeley) 6/4/93
.\"
.Dd June 10, 2004
.Dt BYTEORDER 3
.Os
.Sh NAME
.Nm htonl ,
.Nm htons ,
.Nm ntohl ,
.Nm ntohs
.Nd convert values between host and network byte order
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In arpa/inet.h
.Ft uint32_t
.Fn htonl "uint32_t host32"
.Ft uint16_t
.Fn htons "uint16_t host16"
.Ft uint32_t
.Fn ntohl "uint32_t net32"
.Ft uint16_t
.Fn ntohs "uint16_t net16"
.Sh DESCRIPTION
These routines convert 16 and 32 bit quantities between network
byte order and host byte order.
.Pp
On machines which have a byte order which is the same as the network
order, these routines are defined as macros that expand to the value of
their argument.
.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
.Fn htonl ,
.Fn htons ,
.Fn ntohl ,
and
.Fn ntohs
functions conform to
.St -p1003.1-2001 .
Their use of the fixed-width integer types
.Fa uint16_t
and
.Fa uint32_t
first appeared in
.St -xns5 .
.Sh HISTORY
The
.Nm byteorder
functions appeared in
.Bx 4.2 .
.Sh BUGS
The `l' and `s' suffixes in the names are not meaningful in machines
where long integers are not 32 bits.