title: error: expected unqualified-id on extern "C"
body: <p>I have a cpp code in which I want to call a c function.
  Both compile well to .o files, but when the clang++ is executing for compilation, I receive the following error:</p>
  
  <pre><code>file.cpp:74:12: error: expected unqualified-id
      extern "C"
             ^
  </code></pre>
  
  <p>The code in the cpp file is the following:</p>
  
  <pre><code>void parseExtern(QString str)
  {
  #ifdef __cplusplus
      extern "C"
      {
  #endif
          function_in_C(str);
  #ifdef __cplusplus
      }
  #endif
  
  }
  </code></pre>
  
  <p>How can I avoid the error ? I can't compile the c file with clang++, I really need to use extern. Thanks.</p>