title: What changed with "converting constructor"s at C++11?
body: <p>Today I was surprised by <a href="https://en.cppreference.com/w/cpp/language/converting_constructor" rel="nofollow noreferrer">this paragraph at cppreference</a>:</p>
  <blockquote>
  <p>Converting constructor</p>
  <p>A constructor that is not declared with the specifier explicit and which can be called with a single parameter (<em>until C++11</em>) is called a <em>converting constructor</em>.</p>
  </blockquote>
  <p>The &quot;(until C++11)&quot; bit seems to be referring to the phrase &quot;which can be called with a single parameter&quot;.</p>
  <p>I didn't know this changed at C++11.  What's the change?  What kind of &quot;converting constructor&quot; can take more than one argument? (If that's what it is referring to.)</p>
  <p>(I suppose it could be referring to constructors that have more than one argument but those extra arguments - or all of them - have default values.  But default values for arguments have been in C++ forever. So did something change there - before C++11 you couldn't implicitly convert with a constructor that took default arguments?  But <a href="https://wandbox.org/permlink/IiJtzXUXJwduTdUh" rel="nofollow noreferrer">this example at wandbolt</a> shows that that <em>did</em> work in C++03.)</p>