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<html><head><title>Net::hostent (Programming Perl)</title><!-- STYLESHEET --><link rel="stylesheet" type="text/css" href="../style/style1.css"><!-- METADATA --><!--Dublin Core Metadata--><meta name="DC.Creator" content=""><meta name="DC.Date" content=""><meta name="DC.Format" content="text/xml" scheme="MIME"><meta name="DC.Generator" content="XSLT stylesheet, xt by James Clark"><meta name="DC.Identifier" content=""><meta name="DC.Language" content="en-US"><meta name="DC.Publisher" content="O'Reilly &amp; Associates, Inc."><meta name="DC.Source" content="" scheme="ISBN"><meta name="DC.Subject.Keyword" content=""><meta name="DC.Title" content="Net::hostent"><meta name="DC.Type" content="Text.Monograph"></head><body><!-- START OF BODY --><!-- TOP BANNER --><img src="gifs/smbanner.gif" usemap="#banner-map" border="0" alt="Book Home"><map name="banner-map"><AREA SHAPE="RECT" COORDS="0,0,466,71" HREF="index.htm" ALT="Programming Perl"><AREA SHAPE="RECT" COORDS="467,0,514,18" HREF="jobjects/fsearch.htm" ALT="Search this book"></map><!-- TOP NAV BAR --><div class="navbar"><table width="515" border="0"><tr><td align="left" valign="top" width="172"><a href="ch32_34.htm"><img src="../gifs/txtpreva.gif" alt="Previous" border="0"></a></td><td align="center" valign="top" width="171"><a href="ch32_01.htm">Chapter 32: Standard Modules</a></td><td align="right" valign="top" width="172"><a href="ch32_36.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0"></a></td></tr></table></div><hr width="515" align="left"><!-- SECTION BODY --><h2 class="sect1">32.35. Net::hostent</h2><p><blockquote><pre class="programlisting">use Socket;use Net::hostent;print inet_ntoa(gethost("www.perl.com")-&gt;addr);  # prints 208.201.239.50printf "%vd", gethost("www.perl.com")-&gt;addr;     # same thingprint gethost("127.0.0.1")-&gt;name;                # prints localhostuse Net::hostent ':FIELDS';if (gethost($name_or_number)) {    print "name is $h_name\n";    print "aliases are $h_aliases\n";    print "addrs are ",        join ", " =&gt; map { inet_ntoa($_) } @h_addr_list;}</pre></blockquote>This module's default exports override the core<tt class="literal">gethostbyname</tt> and <tt class="literal">gethostbyaddr</tt>functions, replacing them with versions that return a<tt class="literal">Net::hostent</tt> object (or <tt class="literal">undef</tt> onfailure).  This object has attribute accessor methods that return thelike-named structure field name from the C library's <tt class="literal">structhostent</tt> from <em class="emphasis">netdb.h</em>:<tt class="literal">name</tt>, <tt class="literal">aliases</tt>,<tt class="literal">addrtype</tt>, <tt class="literal">length</tt>, or<tt class="literal">addr_list</tt>.  The <tt class="literal">aliases</tt> and<tt class="literal">addr_list</tt> methods return array references; the restreturn scalars.  The <tt class="literal">addr</tt> method is equivalent tothe initial element in the <tt class="literal">addr_list</tt> arrayreference.  The <tt class="literal">gethost</tt> function is a frontend thatforwards a numeric argument to <tt class="literal">gethostbyaddr</tt> by wayof the <tt class="literal">Socket::inet_aton</tt>function and the rest to<tt class="literal">gethostbyname</tt>.  As with the other semipragmaticmodules that override list-returning built-ins, if you import the"<tt class="literal">:FIELDS</tt>" tag, you can access scalar or arraypackage variables by the same names as the method calls by using aleading "<tt class="literal">h_</tt>".  This still overrides your corefunctions, though.</p><!-- BOTTOM NAV BAR --><hr width="515" align="left"><div class="navbar"><table width="515" border="0"><tr><td align="left" valign="top" width="172"><a href="ch32_34.htm"><img src="../gifs/txtpreva.gif" alt="Previous" border="0"></a></td><td align="center" valign="top" width="171"><a href="index.htm"><img src="../gifs/txthome.gif" alt="Home" border="0"></a></td><td align="right" valign="top" width="172"><a href="ch32_36.htm"><img src="../gifs/txtnexta.gif" alt="Next" border="0"></a></td></tr><tr><td align="left" valign="top" width="172">32.34. Math::Trig</td><td align="center" valign="top" width="171"><a href="index/index.htm"><img src="../gifs/index.gif" alt="Book Index" border="0"></a></td><td align="right" valign="top" width="172">32.36. POSIX</td></tr></table></div><hr width="515" align="left"><!-- LIBRARY NAV BAR --><img src="../gifs/smnavbar.gif" usemap="#library-map" border="0" alt="Library Navigation Links"><p><font size="-1"><a href="copyrght.htm">Copyright &copy; 2001</a> O'Reilly &amp; Associates. All rights reserved.</font></p><map name="library-map"> <area shape="rect" coords="2,-1,79,99" href="../index.htm"><area shape="rect" coords="84,1,157,108" href="../perlnut/index.htm"><area shape="rect" coords="162,2,248,125" href="../prog/index.htm"><area shape="rect" coords="253,2,326,130" href="../advprog/index.htm"><area shape="rect" coords="332,1,407,112" href="../cookbook/index.htm"><area shape="rect" coords="414,2,523,103" href="../sysadmin/index.htm"></map><!-- END OF BODY --></body></html>
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