<refentry xmlns="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>2004</year>

<year>2005</year>

<year>2007</year>

<year>2014</year>

<year>2015</year>

<year>2016</year>

<holder>Internet Systems Consortium, Inc. ("ISC")</holder>

</copyright>

<copyright>

<year>2000</year>

<year>2001</year>

<holder>Internet Software Consortium.</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 &lt;lwres/netdb.h&gt;</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>