ibm-information-center/dist/eclipse/plugins/i5OS.ic.apis_5.4.0.1/ghosti.htm

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<title>gethostid()--Retrieve Host ID</title>
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<h2>gethostid()--Retrieve Host ID</h2>
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<br>
&nbsp;&nbsp;Syntax<br>
<pre>
#include &lt;sys/types.h&gt;
#include &lt;sys/socket.h&gt;
int gethostid()
</pre>
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&nbsp;&nbsp;Service Program Name: QSOSRV1<br>
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&nbsp;&nbsp;Default Public Authority: *USE<br>
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&nbsp;nbsp;Threadsafe: Yes<br>
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<p>The <em>gethostid()</em> function is used to retrieve a host's ID.</p>
<br>
<h3>Authorities</h3>
<p>No authorization is required.</p>
<br>
<h3>Return Value</h3>
<p><em>gethostid()</em> returns an integer. Possible values are:</p>
<ul>
<li>0 when a <em>sethostid()</em> has not been issued previously since the last
initial program load (IPL)<br>
<br>
</li>
<li>n (successful), where n is the number specified on a previously issued
<em>sethostid()</em> call</li>
</ul>
<br>
<h3>Usage Notes</h3>
<ol>
<li>When a process issues a <em>sethostid()</em>, the <em>host_id</em> can be
accessed by any process that issues a <em>gethostid()</em><br>
<br>
</li>
<li>The <em>host_id</em> is reset to zero when an initial program load is
performed.<br>
<br>
</li>
<li>The <em>host_id</em> is a signed integer. Therefore, a -1 return value from
the <em>gethostid()</em> may not indicate an error, but rather that a previous
<em>sethostid()</em> was issued that specified a <em>host_id</em> of -1.<br>
<br>
</li>
<li>While many socket implementations refer to the <em>host_id</em> as the IP
address of the machine, this is not necessarily the case. Many machines that
support the TCP/IP protocol suite support multiple local IP addresses. The
value contained in <em>host_id</em> is <strong>not</strong> used by TCP in any
manner.</li>
</ol>
<br>
<h3>Related Information</h3>
<ul>
<li><a href="shosti.htm">sethostid()</a>--Set Host ID Address<br>
<br>
</li>
<li><a href="ghostn.htm">gethostname()</a>--Retrieve Host Name<br>
<br>
</li>
<li><a href="shostn.htm">sethostname()</a>--Set Host Name</li>
</ul>
<br>
<hr>
API introduced: V3R1
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