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| <div class="titlepage"><div><div><h4 class="title"> |
| <a name="fusion.iterator.metafunctions.value_of"></a><a class="link" href="value_of.html" title="value_of">value_of</a> |
| </h4></div></div></div> |
| <a name="fusion.iterator.metafunctions.value_of.description"></a><h6> |
| <a name="id858328"></a> |
| <a class="link" href="value_of.html#fusion.iterator.metafunctions.value_of.description">Description</a> |
| </h6> |
| <p> |
| Returns the type stored at the position of an iterator. |
| </p> |
| <a name="fusion.iterator.metafunctions.value_of.synopsis"></a><h6> |
| <a name="id858345"></a> |
| <a class="link" href="value_of.html#fusion.iterator.metafunctions.value_of.synopsis">Synopsis</a> |
| </h6> |
| <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> |
| <span class="keyword">typename</span> <span class="identifier">I</span> |
| <span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">value_of</span> |
| <span class="special">{</span> |
| <span class="keyword">typedef</span> <span class="emphasis"><em>unspecified</em></span> <span class="identifier">type</span><span class="special">;</span> |
| <span class="special">};</span> |
| </pre> |
| <div class="table"> |
| <a name="id858417"></a><p class="title"><b>Table 1.12. Parameters</b></p> |
| <div class="table-contents"><table class="table" summary="Parameters"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Parameter |
| </p> |
| </th> |
| <th> |
| <p> |
| Requirement |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| </tr></thead> |
| <tbody><tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">I</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Model of <a class="link" href="../concepts/forward_iterator.html" title="Forward Iterator">Forward |
| Iterator</a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Operation's argument |
| </p> |
| </td> |
| </tr></tbody> |
| </table></div> |
| </div> |
| <br class="table-break"><a name="fusion.iterator.metafunctions.value_of.expression_semantics"></a><h6> |
| <a name="id858507"></a> |
| <a class="link" href="value_of.html#fusion.iterator.metafunctions.value_of.expression_semantics">Expression |
| Semantics</a> |
| </h6> |
| <pre class="programlisting"><a class="link" href="value_of.html" title="value_of"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">value_of</span></code></a><span class="special"><</span><span class="identifier">I</span><span class="special">>::</span><span class="identifier">type</span> |
| </pre> |
| <p> |
| <span class="bold"><strong>Return type</strong></span>: Any type |
| </p> |
| <p> |
| <span class="bold"><strong>Semantics</strong></span>: Returns the type stored in |
| a sequence at iterator position <code class="computeroutput"><span class="identifier">I</span></code>. |
| </p> |
| <a name="fusion.iterator.metafunctions.value_of.header"></a><h6> |
| <a name="id858581"></a> |
| <a class="link" href="value_of.html#fusion.iterator.metafunctions.value_of.header">Header</a> |
| </h6> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">iterator</span><span class="special">/</span><span class="identifier">value_of</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">value_of</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| </pre> |
| <a name="fusion.iterator.metafunctions.value_of.example"></a><h6> |
| <a name="id858689"></a> |
| <a class="link" href="value_of.html#fusion.iterator.metafunctions.value_of.example">Example</a> |
| </h6> |
| <pre class="programlisting"><span class="keyword">typedef</span> <a class="link" href="../../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a><span class="special"><</span><span class="keyword">int</span><span class="special">,</span><span class="keyword">int</span><span class="special">&,</span><span class="keyword">const</span> <span class="keyword">int</span><span class="special">&></span> <span class="identifier">vec</span><span class="special">;</span> |
| <span class="keyword">typedef</span> <a class="link" href="../../sequence/intrinsic/metafunctions/begin.html" title="begin"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">begin</span></code></a><span class="special"><</span><span class="identifier">vec</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">first</span><span class="special">;</span> |
| <span class="keyword">typedef</span> <a class="link" href="next.html" title="next"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">next</span></code></a><span class="special"><</span><span class="identifier">first</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">second</span><span class="special">;</span> |
| <span class="keyword">typedef</span> <a class="link" href="next.html" title="next"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">next</span></code></a><span class="special"><</span><span class="identifier">second</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">third</span><span class="special">;</span> |
| |
| <span class="identifier">BOOST_MPL_ASSERT</span><span class="special">((</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_same</span><span class="special"><</span><a class="link" href="value_of.html" title="value_of"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">value_of</span></code></a><span class="special"><</span><span class="identifier">first</span><span class="special">>::</span><span class="identifier">type</span><span class="special">,</span> <span class="keyword">int</span><span class="special">>));</span> |
| <span class="identifier">BOOST_MPL_ASSERT</span><span class="special">((</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_same</span><span class="special"><</span><a class="link" href="value_of.html" title="value_of"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">value_of</span></code></a><span class="special"><</span><span class="identifier">second</span><span class="special">>::</span><span class="identifier">type</span><span class="special">,</span> <span class="keyword">int</span><span class="special">&>));</span> |
| <span class="identifier">BOOST_MPL_ASSERT</span><span class="special">((</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">is_same</span><span class="special"><</span><a class="link" href="value_of.html" title="value_of"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">value_of</span></code></a><span class="special"><</span><span class="identifier">third</span><span class="special">>::</span><span class="identifier">type</span><span class="special">,</span> <span class="keyword">const</span> <span class="keyword">int</span><span class="special">&>));</span> |
| </pre> |
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