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Next: <a href="va_005farg.html#va_005farg" accesskey="n" rel="next">va_arg</a>, Up: <a href="Stdarg.html#Stdarg" accesskey="u" rel="up">Stdarg</a> &nbsp; [<a href="Document-Index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Document-Index.html#Document-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Initialize-variable-argument-list"></a>
<h4 class="subsection">14.1.1 Initialize variable argument list</h4>
<a name="index-va_005fstart"></a>
<p><strong>Synopsis</strong>
</p><div class="example">
<pre class="example">#include &lt;stdarg.h&gt;
void va_start(va_list <var>ap</var>, <var>rightmost</var>);
</pre></div>

<p><strong>Description</strong><br>
Use <code>va_start</code> to initialize the variable argument list <var>ap</var>,
so that <code>va_arg</code> can extract values from it.  <var>rightmost</var> is
the name of the last explicit argument in the parameter list (the
argument immediately preceding the ellipsis &lsquo;<samp>...</samp>&rsquo; that flags
variable arguments in an ANSI C function header).  You can only use
<code>va_start</code> in a function declared using this ellipsis notation
(not, for example, in one of its subfunctions).
</p>
<p><strong>Returns</strong><br>
<code>va_start</code> does not return a result.
</p>
<p><strong>Portability</strong><br>
ANSI C requires <code>va_start</code>.
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