.\"	$OpenBSD: net_addrcmp.3,v 1.4 2007/05/31 19:19:30 jmc Exp $
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.\" Copyright (c) 1999 Theo de Raadt
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.Dd $Mdocdate: May 31 2007 $
.Dt NET_ADDRCMP 3
.Os
.Sh NAME
.Nm net_addrcmp
.Nd compare socket address structures
.Sh SYNOPSIS
.Fd #include <netdb.h>
.Ft int
.Fn net_addrcmp "struct sockaddr *sa1" "struct sockaddr *sa2"
.Sh DESCRIPTION
The
.Fn net_addrcmp
function compares two socket address structures,
.Fa sa1
and
.Fa sa2 .
.Sh RETURN VALUES
If
.Fa sa1
and
.Fa sa2
are for the same address,
.Fn net_addrcmp
returns 0.
.Pp
The
.Fa sa_len
fields are compared first.
If they do not match,
.Fn net_addrcmp
returns \-1 or 1 if
.Li sa1->sa_len
is less than or greater than
.Li sa2->sa_len ,
respectively.
.Pp
Next, the
.Fa sa_family
members are compared.
If they do not match,
.Fn net_addrcmp
returns \-1 or 1 if
.Li sa1->sa_family
is less than or greater than
.Li sa2->sa_family ,
respectively.
.Pp
Lastly, if each socket address structure's
.Fa sa_len
and
.Fa sa_family
fields match,
the protocol-specific data (the
.Fa sa_data
field) is compared.
If there's a match, both
.Fa sa1
and
.Fa sa2
must refer to the same address, and 0 is returned; otherwise, a value >0
or <0 is returned.
.Sh HISTORY
A
.Fn net_addrcmp
function was added in
.Ox 2.5 .