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<refentry xmlns:db="http://docbook.org/ns/docbook" version="5.0">
<info>
<date>2007-06-18</date>
</info>
<refentryinfo>
<corpname>ISC</corpname>
<corpauthor>Internet Systems Consortium, Inc.</corpauthor>
</refentryinfo>
<refmeta>
<refentrytitle>lwres_getnameinfo</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo>BIND9</refmiscinfo>
</refmeta>
<docinfo>
<copyright>
<year>2000</year>
<year>2001</year>
<year>2004</year>
<year>2005</year>
<year>2007</year>
<year>2014</year>
<year>2015</year>
<year>2016</year>
<year>2018</year>
<year>2019</year>
<year>2020</year>
<holder>Internet Systems Consortium, Inc. ("ISC")</holder>
</copyright>
</docinfo>
<refnamediv>
<refname>lwres_getnameinfo</refname>
<refpurpose>lightweight resolver socket address structure to hostname and
service name
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <lwres/netdb.h></funcsynopsisinfo>
<funcprototype>
<funcdef>
int
<function>lwres_getnameinfo</function></funcdef>
<paramdef>const struct sockaddr *<parameter>sa</parameter></paramdef>
<paramdef>size_t <parameter>salen</parameter></paramdef>
<paramdef>char *<parameter>host</parameter></paramdef>
<paramdef>size_t <parameter>hostlen</parameter></paramdef>
<paramdef>char *<parameter>serv</parameter></paramdef>
<paramdef>size_t <parameter>servlen</parameter></paramdef>
<paramdef>int <parameter>flags</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsection><info><title>DESCRIPTION</title></info>
<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 is
1025 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 length
of the service name is <constant>NI_MAXSERV</constant> - 32
bytes.
</para>
<para>
The <parameter>flags</parameter> argument sets the
following
bits:
<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
and
this 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 datagram
service, and causes getservbyport() to be called with a second
argument of "udp" instead of its default of "tcp". This is
required
for the few ports (512-514) that have different services for UDP
and
TCP.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsection>
<refsection><info><title>RETURN VALUES</title></info>
<para><function>lwres_getnameinfo()</function>
returns 0 on success or a non-zero error code if an error occurs.
</para>
</refsection>
<refsection><info><title>SEE ALSO</title></info>
<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>.
</para>
</refsection>
<refsection><info><title>BUGS</title></info>
<para>
RFC2133 fails to define what the nonzero return values of
<citerefentry>
<refentrytitle>getnameinfo</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>
are.
</para>
</refsection>
</refentry>