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<h4 class="subsection">29.16.3 Testing for Netgroup Membership</h4>

<p>It is often not necessary to scan the whole netgroup since often the
only interesting question is whether a given entry is part of the
selected netgroup.

<!-- netdb.h -->
<!-- BSD -->
<div class="defun">
&mdash; Function: int <b>innetgr</b> (<var>const char *netgroup, const char *host, const char *user, const char *domain</var>)<var><a name="index-innetgr-3429"></a></var><br>
<blockquote><p>This function tests whether the triple specified by the parameters
<var>hostp</var>, <var>userp</var>, and <var>domainp</var> is part of the netgroup
<var>netgroup</var>.  Using this function has the advantage that

          <ol type=1 start=1>
<li>no other netgroup function can use the global netgroup state since
internal locking is used and
<li>the function is implemented more efficiently than successive calls
to the other <code>set</code>/<code>get</code>/<code>endnetgrent</code> functions.
             </ol>

        <p>Any of the pointers <var>hostp</var>, <var>userp</var>, and <var>domainp</var> can be
<code>NULL</code> which means any value is accepted in this position.  This is
also true for the name <code>-</code> which should not match any other string
otherwise.

        <p>The return value is <code>1</code> if an entry matching the given triple is
found in the netgroup.  The return value is <code>0</code> if the netgroup
itself is not found, the netgroup does not contain the triple or
internal errors occurred. 
</p></blockquote></div>

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