NetBSD/lib/libc/net/byteorder.3

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.\" $NetBSD: byteorder.3,v 1.9 2002/02/07 07:00:20 ross Exp $
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.\" @(#)byteorder.3 8.1 (Berkeley) 6/4/93
.\"
.Dd June 4, 1993
.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
.Fd #include \*[Lt]sys/types.h\*[Gt]
.Ft in_addr_t
.Fn htonl "in_addr_t host32"
.Ft in_port_t
.Fn htons "in_port_t host16"
.Ft in_addr_t
.Fn ntohl "in_addr_t net32"
.Ft in_port_t
.Fn ntohs "in_port_t net16"
.Sh DESCRIPTION
These routines convert 16 and 32 bit quantities between network
byte order and host byte order. The types
.Ft in_addr_t
and
.Ft in_port_t
are defined by X/Open as:
.Bd -literal -offset indent
typedef u_int32_t in_addr_t;
typedef u_int16_t in_port_t;
.Ed
.Pp
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 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.