Is there a way to use enable_if so that one specialization gets selected if operator+ exists between two types, and another specialization if operator+ does not exist?  For example:<br><br><br>template&lt;class A, class B, boost::enable_if&lt;operator_plus_exists&lt;A,B&gt; &gt;::type* dummy = 0&gt;<br>
void operator()(const A&amp; a, const B&amp; b)<br>{<br>   std::cout &lt;&lt; &quot;a + b = &quot; &lt;&lt; (a + b) &lt;&lt; std::endl;<br>}<br><br>template&lt;class A, class B, boost::disable_if&lt;operator_plus_exists&lt;A,B&gt; &gt;::type* dummy = 0&gt;<br>
void operator()(const A&amp; a, const B&amp; b)<br>{<br>}<br><br><br>How would I implement the operator_plus_exists class?<br>