lwres_getnameinfo.html revision 2cd182921e1b04ccda0a56995c4cc491c882af04
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<HTML
><HEAD
><TITLE
>lwres_getnameinfo</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.7"></HEAD
><BODY
CLASS="REFENTRY"
BGCOLOR="#FFFFFF"
TEXT="#000000"
LINK="#0000FF"
VLINK="#840084"
ALINK="#0000FF"
><H1
><A
NAME="AEN1"
></A
>lwres_getnameinfo</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN8"
></A
><H2
>Name</H2
>lwres_getnameinfo&nbsp;--&nbsp;lightweight resolver socket address structure to hostname and service name</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN11"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><P
></P
><A
NAME="AEN12"
></A
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include &lt;lwres/netdb.h&gt;</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int
lwres_getnameinfo</CODE
>(const struct sockaddr *sa, size_t salen, char *host, size_t hostlen, char *serv, size_t servlen, int flags);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN24"
></A
><H2
>DESCRIPTION</H2
><P
> This function is equivalent to the <SPAN
CLASS="CITEREFENTRY"
><SPAN
CLASS="REFENTRYTITLE"
>getnameinfo</SPAN
>(3)</SPAN
> function defined in RFC2133.
<CODE
CLASS="FUNCTION"
>lwres_getnameinfo()</CODE
> returns the hostname for the
<SPAN
CLASS="TYPE"
>struct sockaddr</SPAN
> <VAR
CLASS="PARAMETER"
>sa</VAR
> which is
<VAR
CLASS="PARAMETER"
>salen</VAR
> bytes long. The hostname is of length
<VAR
CLASS="PARAMETER"
>hostlen</VAR
> and is returned via
<VAR
CLASS="PARAMETER"
>*host.</VAR
> The maximum length of the hostname is
1025 bytes: <CODE
CLASS="CONSTANT"
>NI_MAXHOST</CODE
>.</P
><P
> The name of the service associated with the port number in
<VAR
CLASS="PARAMETER"
>sa</VAR
> is returned in <VAR
CLASS="PARAMETER"
>*serv.</VAR
>
It is <VAR
CLASS="PARAMETER"
>servlen</VAR
> bytes long. The maximum length
of the service name is <CODE
CLASS="CONSTANT"
>NI_MAXSERV</CODE
> - 32 bytes.</P
><P
> The <VAR
CLASS="PARAMETER"
>flags</VAR
> argument sets the following
bits:
<P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><CODE
CLASS="CONSTANT"
>NI_NOFQDN</CODE
></DT
><DD
><P
>A fully qualified domain name is not required for local hosts.
The local part of the fully qualified domain name is returned instead.</P
></DD
><DT
><CODE
CLASS="CONSTANT"
>NI_NUMERICHOST</CODE
></DT
><DD
><P
>Return the address in numeric form, as if calling inet_ntop(),
instead of a host name.</P
></DD
><DT
><CODE
CLASS="CONSTANT"
>NI_NAMEREQD</CODE
></DT
><DD
><P
>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.</P
></DD
><DT
><CODE
CLASS="CONSTANT"
>NI_NUMERICSERV</CODE
></DT
><DD
><P
>The service name is returned as a digit string representing the port number.</P
></DD
><DT
><CODE
CLASS="CONSTANT"
>NI_DGRAM</CODE
></DT
><DD
><P
>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.</P
></DD
></DL
></DIV
></P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN70"
></A
><H2
>RETURN VALUES</H2
><P
><CODE
CLASS="FUNCTION"
>lwres_getnameinfo()</CODE
>
returns 0 on success or a non-zero error code if an error occurs.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN74"
></A
><H2
>SEE ALSO</H2
><P
><SPAN
CLASS="CITEREFENTRY"
><SPAN
CLASS="REFENTRYTITLE"
>RFC2133</SPAN
></SPAN
>,
<SPAN
CLASS="CITEREFENTRY"
><SPAN
CLASS="REFENTRYTITLE"
>getservbyport</SPAN
>(3)</SPAN
>,
<SPAN
CLASS="CITEREFENTRY"
><SPAN
CLASS="REFENTRYTITLE"
>lwres</SPAN
>(3)</SPAN
>,
<SPAN
CLASS="CITEREFENTRY"
><SPAN
CLASS="REFENTRYTITLE"
>lwres_getnameinfo</SPAN
>(3)</SPAN
>,
<SPAN
CLASS="CITEREFENTRY"
><SPAN
CLASS="REFENTRYTITLE"
>lwres_getnamebyaddr</SPAN
>(3)</SPAN
>.
<SPAN
CLASS="CITEREFENTRY"
><SPAN
CLASS="REFENTRYTITLE"
>lwres_net_ntop</SPAN
>(3)</SPAN
>.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN94"
></A
><H2
>BUGS</H2
><P
>RFC2133 fails to define what the nonzero return values of
<SPAN
CLASS="CITEREFENTRY"
><SPAN
CLASS="REFENTRYTITLE"
>getnameinfo</SPAN
>(3)</SPAN
>
are.</P
></DIV
></BODY
></HTML
>