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<a name="Extract-a-value-from-argument-list"></a>
<h4 class="subsection">14.1.2 Extract a value from argument list</h4>
<a name="index-va_005farg"></a>
<p><strong>Synopsis</strong>
</p><div class="example">
<pre class="example">#include &lt;stdarg.h&gt;
<var>type</var> va_arg(va_list <var>ap</var>, <var>type</var>);
</pre></div>

<p><strong>Description</strong><br>
<code>va_arg</code> returns the next unprocessed value from a variable
argument list <var>ap</var> (which you must previously create with
<var>va_start</var>).  Specify the type for the value as the second parameter
to the macro, <var>type</var>.
</p>
<p>You may pass a <code>va_list</code> object <var>ap</var> to a subfunction, and use
<code>va_arg</code> from the subfunction rather than from the function
actually declared with an ellipsis in the header; however, in that case
you may <em>only</em> use <code>va_arg</code> from the subfunction.  ANSI C does
not permit extracting successive values from a single variable-argument
list from different levels of the calling stack.
</p>
<p>There is no mechanism for testing whether there is actually a next
argument available; you might instead pass an argument count (or some
other data that implies an argument count) as one of the fixed arguments
in your function call.
</p>
<p><strong>Returns</strong><br>
<code>va_arg</code> returns the next argument, an object of type <var>type</var>.
</p>
<p><strong>Portability</strong><br>
ANSI C requires <code>va_arg</code>.
</p>


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