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| <h2><span class="refentrytitle">Struct template is_aggregate</span></h2> |
| <p>boost::proto::is_aggregate — A Boolean metafunction that indicates whether a type requires aggregate initialization. </p> |
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| <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> |
| <div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../../proto/reference.html#header.boost.proto.traits_hpp" title="Header <boost/proto/traits.hpp>">boost/proto/traits.hpp</a>> |
| |
| </span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> |
| <span class="keyword">struct</span> <a class="link" href="is_aggregate.html" title="Struct template is_aggregate">is_aggregate</a> <span class="special">:</span> <span class="keyword"></span> mpl::bool_<<em class="replaceable"><code>true-or-false</code></em>> <span class="special">{</span> |
| <span class="special">}</span><span class="special">;</span></pre></div> |
| <div class="refsect1"> |
| <a name="id2379777"></a><h2>Description</h2> |
| <p> |
| <code class="computeroutput">proto::is_aggregate<></code> is used by the |
| <code class="computeroutput"><a class="link" href="make.html" title="Struct template make">proto::make<></a></code> transform to determine how |
| to construct an object of some type <code class="computeroutput">T</code>, given some initialization arguments |
| <code class="computeroutput">a<sub>0</sub>,...a<sub>n</sub></code>. |
| If <code class="computeroutput">proto::is_aggregate<T>::value</code> is <code class="computeroutput">true</code>, |
| then an object of type <code class="computeroutput">T</code> will be initialized as |
| <code class="computeroutput">T t = {a<sub>0</sub>,...a<sub>n</sub>};</code>. |
| Otherwise, it will be initialized as |
| <code class="computeroutput">T t(a<sub>0</sub>,...a<sub>n</sub>)</code>. |
| </p> |
| <p> |
| Note: <code class="computeroutput"><a class="link" href="expr.html" title="Struct template expr">proto::expr<></a></code> and |
| <code class="computeroutput"><a class="link" href="basic_expr.html" title="Struct template basic_expr">proto::basic_expr<></a></code>are aggregates. |
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| <td align="right"><div class="copyright-footer">Copyright © 2008 Eric Niebler<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) |
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