title: Create an identifier at compile time that has the line number as part of it
body: <p>I want a C++ preprocessor macro that creates a new identifier with the line number as part of it. This is for using the identifier as a throwaway variable that doesn't collide with any other variable name. For e.g., if I write</p>
  
  <pre><code>VARNAME("Var")
  </code></pre>
  
  <p>at line number 100 of a file, I want the preprocessor to generate the variable name:</p>
  
  <pre><code>Var100
  </code></pre>
  
  <p>How do I do this please? I know I have to use stringification and the <code>__LINE__</code> predefined macro, but I cannot quite figure out how to put it all together.</p>