title: Does extern "C" have any effect in C?
body: <p>I just got some C code that uses extern "C" to declare external functions like this:</p>
  
  <pre><code>extern "C" void func();
  </code></pre>
  
  <p>Is this valid C?  I'm getting an error at this line,  but I'm not sure if it's because of this or something else.</p>