.\"	$OpenBSD: iso_addr.3,v 1.2 1996/08/19 08:29:22 tholo Exp $
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.Dd June 4, 1993
.Dt ISO_ADDR 3
.Os
.Sh NAME
.Nm iso_addr ,
.Nm iso_ntoa
.Nd "elementary network address conversion routines for Open System Interconnection
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <netiso/iso.h>
.Ft struct iso_addr *
.Fn iso_addr "char *cp"
.Ft char *
.Fn iso_ntoa "struct iso_addr *isoa"
.Sh DESCRIPTION
The routine
.Fn iso_addr
interprets character strings representing
.Tn OSI
addresses, returning binary information suitable
for use in system calls.
The routine
.Fn iso_ntoa
takes
.Tn OSI
addresses and returns
.Tn ASCII
strings representing NSAPs (network service
access points) in a
notation inverse to that accepted by 
.Fn iso_addr .
.Pp
Unfortunately, no universal standard exists for representing
.Tn OSI
network addresses.
.Pp
The format employed by
.Fn iso_addr
is a sequence of hexadecimal
.Dq digits
(optionally separated by periods),
of the form:
.Bd -filled -offset indent
<hex digits>.<hex digits>.<hex digits>
.Ed
.Pp
Each pair of hexadecimal digits represents a byte
with the leading digit indicating the higher-ordered bits.
A period following an even number of bytes has no
effect (but may be used to increase legibility).
A period following an odd number of bytes has the
effect of causing the byte of address being translated
to have its higher order bits filled with zeros.
.Sh RETURN VALUES
.Fn iso_ntoa
always returns a null terminated string.
.Fn iso_addr
always returns a pointer to a struct iso_addr.
(See
.Sx BUGS . )
.Sh SEE ALSO
.Xr iso 4
.Sh HISTORY
The
.Fn iso_addr
and
.Fn iso_ntoa
functions appeared in 
.Bx 4.3 Reno .
.Sh BUGS
The returned values
reside in a static memory area.
.Pp
The function
.Fn iso_addr
should diagnose improperly formed input, and there should be an unambiguous
way to recognize this.