title: How do I stream into a string without creating a named stringstream?
body: <p>I often end up writing code like this:</p>
  
  <pre><code>SomeStreamableType x;
  std::stringstream ss;
  ss &lt;&lt; "Value is: " &lt;&lt; x;
  log(ss.str());
  </code></pre>
  
  <p>The extra line needed to generate the stringstream feels superfulous. I can do this, but it's equally cumbersom:</p>
  
  <pre><code>SomeStreamableType x;
  const std::string str =  "Value is: " + boost::lexical_cast&lt;std::string&gt;(x);
  log(str);
  </code></pre>
  
  <p>I want to be able to do this:</p>
  
  <pre><code>SomeStreamableType x;
  log(std::stringstream() &lt;&lt; "Value is: " &lt;&lt; x);
  </code></pre>
  
  <p>Have others encountered this issue and come up with a workaround? <strong>I don't want to create any helper functions or classes</strong>.</p>