title: C/C++ macro string concatenation
body: <pre><code>#define STR1      &quot;s&quot;
  #define STR2      &quot;1&quot;
  #define STR3      STR1 ## STR2
  </code></pre>
  <p>Is it possible to concatenate <code>STR1</code> and <code>STR2</code>, to <code>&quot;s1&quot;</code>?
  You can do this by passing args to another Macro function. But is there a direct way?</p>