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    <p>It's fairly simple to do with parameter pack expansion, even if you can't rewrite <code>f</code> to return the output parameter by value:</p> <pre><code>struct pass { template&lt;typename ...T&gt; pass(T...) {} }; template&lt;typename... Args&gt; void h(Args... args) { const size_t nargs = sizeof...(args); // get number of args X x_array[nargs]; // create X array of that size X *x = x_array; int unused[]{(f(*x++, args), 1)...}; // call f pass{unused}; g(x_array, nargs); // call g with x_array } </code></pre> <p>It should be possible just to write</p> <pre><code> pass{(f(*x++, args), 1)...}; // call f </code></pre> <p>but it appears g++ (4.7.1 at least) has a bug where it fails to order the evaluation of brace-initializer-list parameters as class initialisers. Array initialisers are OK though; see <a href="https://stackoverflow.com/questions/10764867/sequencing-among-a-variadic-expansion">Sequencing among a variadic expansion</a> for more information and examples.</p> <p><a href="http://liveworkspace.org/code/f88c255cbfd03830476f31768eca8183" rel="nofollow noreferrer">Live example</a>.</p> <hr> <p>As an alternative, here's the technique mentioned by Xeo using a generated index pack; unfortunately it does require an extra function call and parameter, but it is reasonably elegant (especially if you happen to have an index pack generator lying around):</p> <pre><code>template&lt;int... I&gt; struct index { template&lt;int n&gt; using append = index&lt;I..., n&gt;; }; template&lt;int N&gt; struct make_index { typedef typename make_index&lt;N - 1&gt;::type::template append&lt;N - 1&gt; type; }; template&lt;&gt; struct make_index&lt;0&gt; { typedef index&lt;&gt; type; }; template&lt;int N&gt; using indexer = typename make_index&lt;N&gt;::type; template&lt;typename... Args, int... i&gt; void h2(index&lt;i...&gt;, Args... args) { const size_t nargs = sizeof...(args); // get number of args X x_array[nargs]; // create X array of that size pass{(f(x_array[i], args), 1)...}; // call f g(x_array, nargs); // call g with x_array } template&lt;typename... Args&gt; void h(Args... args) { h2(indexer&lt;sizeof...(args)&gt;(), std::forward&lt;Args&gt;(args)...); } </code></pre> <p>See <a href="https://stackoverflow.com/questions/10766112/c11-i-can-go-from-multiple-args-to-tuple-but-can-i-go-from-tuple-to-multiple">C++11: I can go from multiple args to tuple, but can I go from tuple to multiple args?</a> for more information. <a href="http://liveworkspace.org/code/44e8ec1545dcbdad55d448c603195c3d" rel="nofollow noreferrer">Live example</a>.</p>
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    1. POCalling a function for each variadic template argument and an array
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    1. COIs the parameter pack guaranteed to be evaluated in order? I seem to remember that it isn't, but I could be misremembering.
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    2. CO@AndrewTomazos-Fathomling parameter packs don't have any special evaluation order; here I'm using a brace-enclosed list which is guaranteed to be evaluated left-right (8.5.4:4).
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    3. COYou don't need `std::forward` if you don't make `h` accept universal references (`Args&&...`).
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