184 lines
4.6 KiB
HTML
184 lines
4.6 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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"http://www.w3.org/TR/html4/strict.dtd">
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<html>
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<head>
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<meta name="description" content="LuaSocket: DNS support">
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<meta name="keywords" content="Lua, LuaSocket, DNS, Network, Library, Support">
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<title>LuaSocket: DNS support</title>
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<link rel="stylesheet" href="reference.css" type="text/css">
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</head>
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<body>
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<!-- header +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
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<div class="header">
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<hr>
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<center>
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<table summary="LuaSocket logo">
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<tr><td align="center"><a href="http://www.lua.org">
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<img width="128" height="128" border="0" alt="LuaSocket" src="luasocket.png">
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</a></td></tr>
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<tr><td align="center" valign="top">Network support for the Lua language
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</td></tr>
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</table>
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<p class="bar">
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<a href="index.html">home</a> ·
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<a href="index.html#download">download</a> ·
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<a href="installation.html">installation</a> ·
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<a href="introduction.html">introduction</a> ·
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<a href="reference.html">reference</a>
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</p>
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</center>
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<hr>
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</div>
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<!-- dns ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
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<h2 id="dns">DNS</h2>
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<p>
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IPv4 name resolution functions
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<a href="#toip"><tt>dns.toip</tt></a>
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and
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<a href="#tohostname"><tt>dns.tohostname</tt></a>
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return <em>all</em> information obtained from
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the resolver in a table of the form:
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</p>
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<blockquote><tt>
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resolved4 = {<br>
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name = <i>canonic-name</i>,<br>
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alias = <i>alias-list</i>,<br>
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ip = <i>ip-address-list</i><br>
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}
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</tt> </blockquote>
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<p>
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Note that the <tt>alias</tt> list can be empty.
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</p>
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<p>
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The more general name resolution function
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<a href="#getaddrinfo"><tt>dns.getaddrinfo</tt></a>, which
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supports both IPv6 and IPv4,
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returns <em>all</em> information obtained from
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the resolver in a table of the form:
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</p>
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<blockquote><tt>
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resolved6 = {<br>
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[1] = {<br>
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family = <i>family-name-1</i>,<br>
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addr = <i>address-1</i><br>
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},<br>
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...<br>
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[n] = {<br>
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family = <i>family-name-n</i>,<br>
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addr = <i>address-n</i><br>
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}<br>
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}
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</tt> </blockquote>
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<p>
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Here, <tt>family</tt> contains the string <tt>"inet"</tt> for IPv4
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addresses, and <tt>"inet6"</tt> for IPv6 addresses.
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</p>
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<!-- getaddrinfo ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
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<p class="name" id="getaddrinfo">
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socket.dns.<b>getaddrinfo(</b>address<b>)</b>
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</p>
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<p class="description">
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Converts from host name to address.
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</p>
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<p class="parameters">
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<tt>Address</tt> can be an IPv4 or IPv6 address or host name.
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</p>
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<p class="return">
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The function returns a table with all information returned by
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the resolver. In case of error, the function returns <b><tt>nil</tt></b>
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followed by an error message.
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</p>
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<!-- gethostname ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
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<p class="name" id="gethostname">
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socket.dns.<b>gethostname()</b>
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</p>
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<p class="description">
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Returns the standard host name for the machine as a string.
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</p>
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<!-- tohostname +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
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<p class="name" id="tohostname">
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socket.dns.<b>tohostname(</b>address<b>)</b>
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</p>
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<p class="description">
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Converts from IPv4 address to host name.
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</p>
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<p class="parameters">
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<tt>Address</tt> can be an IP address or host name.
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</p>
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<p class="return">
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The function returns a string with the canonic host name of the given
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<tt>address</tt>, followed by a table with all information returned by
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the resolver. In case of error, the function returns <b><tt>nil</tt></b>
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followed by an error message.
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</p>
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<!-- toip +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
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<p class="name" id="toip">
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socket.dns.<b>toip(</b>address<b>)</b>
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</p>
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<p class="description">
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Converts from host name to IPv4 address.
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</p>
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<p class="parameters">
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<tt>Address</tt> can be an IP address or host name.
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</p>
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<p class="return">
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Returns a string with the first IP address found for <tt>address</tt>,
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followed by a table with all information returned by the resolver.
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In case of error, the function returns <b><tt>nil</tt></b> followed by an error
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message.
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</p>
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<!-- footer +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ -->
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<div class="footer">
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<hr>
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<center>
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<p class="bar">
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<a href="index.html">home</a> ·
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<a href="index.html#down">download</a> ·
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<a href="installation.html">installation</a> ·
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<a href="introduction.html">introduction</a> ·
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<a href="reference.html">reference</a>
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</p>
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<p>
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<small>
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Last modified by Diego Nehab on <br>
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Thu Apr 20 00:25:07 EDT 2006
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</small>
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</p>
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</center>
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</div>
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</body>
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</html>
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