title: What does int & mean
body: <p>A C++ question,</p>
  
  <p>I know </p>
  
  <pre><code>int* foo(void)
  </code></pre>
  
  <p>foo will return a pointer to int type</p>
  
  <p>how about </p>
  
  <pre><code>int &amp;foo(void)
  </code></pre>
  
  <p>what does it return?</p>
  
  <p>Thank a lot!</p>