 to ease work with boost.system, joining its boost::system name...">boost.system</a> uses this as authorization to make <code>enum</code> <code>Code</code> convertible to <code>Error_code</code>. </p>
<p >The non-specialized version of this sets <code>value</code> to <code>false</code>, so that random arbitary <code>enum</code>s can't just be used as <code>Error_code</code>s. Note that this is the offical way to accomplish that, as (confusingly but formally) documented in <a class="el" href="namespaceboost_