title: ld: undefined symbol vs ld: undefined reference
body: <p>What is the difference between these errors in GNU Binutils ld ? </p>
  
  <ul>
  <li>undefined reference</li>
  <li>undefined symbol</li>
  </ul>
  
  <p>I have a good understanding of undefined reference: This occurs for example when the loader cannot find the implementation of a function.  I am curious to know the cause of undefined symbol. </p>