<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.1//EN"><!-- - Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC") - Copyright (C) 2001  Internet Software Consortium. - - Permission to use, copy, modify, and distribute this software for any - purpose with or without fee is hereby granted, provided that the above - copyright notice and this permission notice appear in all copies. - - THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH - REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY - AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, - INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM - LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE - OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR - PERFORMANCE OF THIS SOFTWARE.--><!-- $Id: lwres_getnameinfo.docbook,v 1.2 2004/09/20 18:00:50 mcr Exp $ --><refentry><refentryinfo><date>Jun 30, 2000</date></refentryinfo><refmeta><refentrytitle>lwres_getnameinfo</refentrytitle><manvolnum>3</manvolnum><refmiscinfo>BIND9</refmiscinfo></refmeta><refnamediv><refname>lwres_getnameinfo</refname><refpurpose>lightweight resolver socket address structure to hostname and service name</refpurpose></refnamediv><refsynopsisdiv><funcsynopsis><funcsynopsisinfo>#include &lt;lwres/netdb.h&gt;</funcsynopsisinfo><funcprototype><funcdef>int<function>lwres_getnameinfo</function></funcdef><paramdef>const struct sockaddr *sa</paramdef><paramdef>size_t salen</paramdef><paramdef>char *host</paramdef><paramdef>size_t hostlen</paramdef><paramdef>char *serv</paramdef><paramdef>size_t servlen</paramdef><paramdef>int flags</paramdef></funcprototype></funcsynopsis></refsynopsisdiv><refsect1><title>DESCRIPTION</title><para> This function is equivalent to the <citerefentry><refentrytitle>getnameinfo</refentrytitle><manvolnum>3</manvolnum></citerefentry> function defined in RFC2133.<function>lwres_getnameinfo()</function> returns the hostname for the<type>struct sockaddr</type> <parameter>sa</parameter> which is<parameter>salen</parameter> bytes long.  The hostname is of length<parameter>hostlen</parameter> and is returned via<parameter>*host.</parameter> The maximum length of the hostname is1025 bytes: <constant>NI_MAXHOST</constant>.</para><para> The name of the service associated with the port number in<parameter>sa</parameter> is returned in <parameter>*serv.</parameter>It is <parameter>servlen</parameter> bytes long.  The maximum lengthof the service name is <constant>NI_MAXSERV</constant> - 32 bytes.</para><para> The <parameter>flags</parameter> argument sets the followingbits:<variablelist><varlistentry><term><constant>NI_NOFQDN</constant></term><listitem><para>A fully qualified domain name is not required for local hosts.The local part of the fully qualified domain name is returned instead.</para></listitem></varlistentry><varlistentry><term><constant>NI_NUMERICHOST</constant></term><listitem><para>Return the address in numeric form, as if calling inet_ntop(),instead of a host name.</para></listitem></varlistentry><varlistentry><term><constant>NI_NAMEREQD</constant></term><listitem><para>A name is required. If the hostname cannot be found in the DNS andthis flag is set, a non-zero error code is returned.If the hostname is not found and the flag is not set, the address is returned in numeric form.</para></listitem></varlistentry><varlistentry><term><constant>NI_NUMERICSERV</constant></term><listitem><para>The service name is returned as a digit string representing the port number.</para></listitem></varlistentry><varlistentry><term><constant>NI_DGRAM</constant></term><listitem><para>Specifies that the service being looked up is a datagramservice,  and causes getservbyport() to be called with a secondargument of "udp" instead of its default of "tcp".  This is requiredfor the few ports (512-514) that have different services for UDP andTCP.</para></listitem></varlistentry></variablelist></para></refsect1><refsect1><title>RETURN VALUES</title><para><function>lwres_getnameinfo()</function>returns 0 on success or a non-zero error code if an error occurs.</para></refsect1><refsect1><title>SEE ALSO</title><para><citerefentry><refentrytitle>RFC2133</refentrytitle></citerefentry>,<citerefentry><refentrytitle>getservbyport</refentrytitle><manvolnum>3</manvolnum></citerefentry>,<citerefentry><refentrytitle>lwres</refentrytitle><manvolnum>3</manvolnum></citerefentry>,<citerefentry><refentrytitle>lwres_getnameinfo</refentrytitle><manvolnum>3</manvolnum></citerefentry>,<citerefentry><refentrytitle>lwres_getnamebyaddr</refentrytitle><manvolnum>3</manvolnum></citerefentry>.<citerefentry><refentrytitle>lwres_net_ntop</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</refsect1><refsect1><title>BUGS</title><para>RFC2133 fails to define what the nonzero return values of<citerefentry><refentrytitle>getnameinfo</refentrytitle><manvolnum>3</manvolnum></citerefentry>are.</para></refsect1></refentry>