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<title>Net::hostent - by-name interface to Perl's built-in gethost* functions</title>
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<h1><a>Net::hostent - by-name interface to Perl's built-in gethost* functions</a></h1>
<p><a name="__index__"></a></p>
<!-- INDEX BEGIN -->
<ul>
<li><a href="#name">NAME</a></li>
<li><a href="#synopsis">SYNOPSIS</a></li>
<li><a href="#description">DESCRIPTION</a></li>
<li><a href="#examples">EXAMPLES</a></li>
<li><a href="#note">NOTE</a></li>
<li><a href="#author">AUTHOR</a></li>
</ul>
<!-- INDEX END -->
<hr />
<p>
</p>
<h1><a name="name">NAME</a></h1>
<p>Net::hostent - by-name interface to Perl's built-in gethost*() functions</p>
<p>
</p>
<hr />
<h1><a name="synopsis">SYNOPSIS</a></h1>
<pre>
<span class="keyword">use</span> <span class="variable">Net::hostent</span><span class="operator">;</span>
</pre>
<p>
</p>
<hr />
<h1><a name="description">DESCRIPTION</a></h1>
<p>This module's default exports override the core <a href="../../lib/Pod/perlfunc.html#item_gethostbyname"><code>gethostbyname()</code></a> and
<a href="../../lib/Pod/perlfunc.html#item_gethostbyaddr"><code>gethostbyaddr()</code></a> functions, replacing them with versions that return
"Net::hostent" objects. This object has methods that return the similarly
named structure field name from the C's hostent structure from <em>netdb.h</em>;
namely name, aliases, addrtype, length, and addr_list. The aliases and
addr_list methods return array reference, the rest scalars. The addr
method is equivalent to the zeroth element in the addr_list array
reference.</p>
<p>You may also import all the structure fields directly into your namespace
as regular variables using the :FIELDS import tag. (Note that this still
overrides your core functions.) Access these fields as variables named
with a preceding <code>h_</code>. Thus, <code>$host_obj->name()</code> corresponds to
$h_name if you import the fields. Array references are available as
regular array variables, so for example <code>@{ $host_obj->aliases()
}</code> would be simply @h_aliases.</p>
<p>The <code>gethost()</code> function is a simple front-end that forwards a numeric
argument to <a href="../../lib/Pod/perlfunc.html#item_gethostbyaddr"><code>gethostbyaddr()</code></a> by way of Socket::inet_aton, and the rest
to gethostbyname().</p>
<p>To access this functionality without the core overrides,
pass the <a href="../../lib/Pod/perlfunc.html#item_use"><code>use</code></a> an empty import list, and then access
function functions with their full qualified names.
On the other hand, the built-ins are still available
via the <code>CORE::</code> pseudo-package.</p>
<p>
</p>
<hr />
<h1><a name="examples">EXAMPLES</a></h1>
<pre>
<span class="keyword">use</span> <span class="variable">Net::hostent</span><span class="operator">;</span>
<span class="keyword">use</span> <span class="variable">Socket</span><span class="operator">;</span>
</pre>
<pre>
<span class="variable">@ARGV</span> <span class="operator">=</span> <span class="operator">(</span><span class="string">'netscape.com'</span><span class="operator">)</span> <span class="keyword">unless</span> <span class="variable">@ARGV</span><span class="operator">;</span>
</pre>
<pre>
<span class="keyword">for</span> <span class="variable">$host</span> <span class="operator">(</span> <span class="variable">@ARGV</span> <span class="operator">)</span> <span class="operator">{</span>
</pre>
<pre>
<span class="keyword">unless</span> <span class="operator">(</span><span class="variable">$h</span> <span class="operator">=</span> <span class="variable">gethost</span><span class="operator">(</span><span class="variable">$host</span><span class="operator">))</span> <span class="operator">{</span>
<span class="keyword">warn</span> <span class="string">"$0: no such host: $host\n"</span><span class="operator">;</span>
<span class="keyword">next</span><span class="operator">;</span>
<span class="operator">}</span>
</pre>
<pre>
<span class="keyword">printf</span> <span class="string">"\n%s is %s%s\n"</span><span class="operator">,</span>
<span class="variable">$host</span><span class="operator">,</span>
<span class="keyword">lc</span><span class="operator">(</span><span class="variable">$h</span><span class="operator">-></span><span class="variable">name</span><span class="operator">)</span> <span class="keyword">eq</span> <span class="keyword">lc</span><span class="operator">(</span><span class="variable">$host</span><span class="operator">)</span> <span class="operator">?</span> <span class="string">""</span> <span class="operator">:</span> <span class="string">"*really* "</span><span class="operator">,</span>
<span class="variable">$h</span><span class="operator">-></span><span class="variable">name</span><span class="operator">;</span>
</pre>
<pre>
<span class="keyword">print</span> <span class="string">"\taliases are "</span><span class="operator">,</span> <span class="keyword">join</span><span class="operator">(</span><span class="string">", "</span><span class="operator">,</span> <span class="variable">@</span><span class="operator">{</span><span class="variable">$h</span><span class="operator">-></span><span class="variable">aliases</span><span class="operator">}</span><span class="operator">),</span> <span class="string">"\n"</span>
<span class="keyword">if</span> <span class="variable">@</span><span class="operator">{</span><span class="variable">$h</span><span class="operator">-></span><span class="variable">aliases</span><span class="operator">}</span><span class="operator">;</span>
</pre>
<pre>
<span class="keyword">if</span> <span class="operator">(</span> <span class="variable">@</span><span class="operator">{</span><span class="variable">$h</span><span class="operator">-></span><span class="variable">addr_list</span><span class="operator">}</span> <span class="operator">></span> <span class="number">1</span> <span class="operator">)</span> <span class="operator">{</span>
<span class="keyword">my</span> <span class="variable">$i</span><span class="operator">;</span>
<span class="keyword">for</span> <span class="variable">$addr</span> <span class="operator">(</span> <span class="variable">@</span><span class="operator">{</span><span class="variable">$h</span><span class="operator">-></span><span class="variable">addr_list</span><span class="operator">}</span> <span class="operator">)</span> <span class="operator">{</span>
<span class="keyword">printf</span> <span class="string">"\taddr #%d is [%s]\n"</span><span class="operator">,</span> <span class="variable">$i</span><span class="operator">++,</span> <span class="variable">inet_ntoa</span><span class="operator">(</span><span class="variable">$addr</span><span class="operator">);</span>
<span class="operator">}</span>
<span class="operator">}</span> <span class="keyword">else</span> <span class="operator">{</span>
<span class="keyword">printf</span> <span class="string">"\taddress is [%s]\n"</span><span class="operator">,</span> <span class="variable">inet_ntoa</span><span class="operator">(</span><span class="variable">$h</span><span class="operator">-></span><span class="variable">addr</span><span class="operator">);</span>
<span class="operator">}</span>
</pre>
<pre>
<span class="keyword">if</span> <span class="operator">(</span><span class="variable">$h</span> <span class="operator">=</span> <span class="keyword">gethostbyaddr</span><span class="operator">(</span><span class="variable">$h</span><span class="operator">-></span><span class="variable">addr</span><span class="operator">))</span> <span class="operator">{</span>
<span class="keyword">if</span> <span class="operator">(</span><span class="keyword">lc</span><span class="operator">(</span><span class="variable">$h</span><span class="operator">-></span><span class="variable">name</span><span class="operator">)</span> <span class="keyword">ne</span> <span class="keyword">lc</span><span class="operator">(</span><span class="variable">$host</span><span class="operator">))</span> <span class="operator">{</span>
<span class="keyword">printf</span> <span class="string">"\tThat addr reverses to host %s!\n"</span><span class="operator">,</span> <span class="variable">$h</span><span class="operator">-></span><span class="variable">name</span><span class="operator">;</span>
<span class="variable">$host</span> <span class="operator">=</span> <span class="variable">$h</span><span class="operator">-></span><span class="variable">name</span><span class="operator">;</span>
<span class="keyword">redo</span><span class="operator">;</span>
<span class="operator">}</span>
<span class="operator">}</span>
<span class="operator">}</span>
</pre>
<p>
</p>
<hr />
<h1><a name="note">NOTE</a></h1>
<p>While this class is currently implemented using the Class::Struct
module to build a struct-like class, you shouldn't rely upon this.</p>
<p>
</p>
<hr />
<h1><a name="author">AUTHOR</a></h1>
<p>Tom Christiansen</p>
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