title: OpenCV C++ with extern "C"
body: <p>I'm currently trying to make a program that uses openCV for taking a picture from a webcam and performing graphical operations to find an area in openCV and then passing it to a .c program which just sends the information to a server via port programming.</p>
  
  <p>my problem is that even though I created a .h file for the functions I used in the openCV .cpp code and included it in my .c, there's still an error saying <code>error: expected ‘)’ before ‘&amp;’ token</code></p>
  
  <p>here is my simpleIS.h:</p>
  
  <pre><code>int captureimg();
  int backgroundsub();
  void noisesuppression(Mat &amp;ptr);
  void simplegetarea(Mat &amp;img);
  
  extern int area1,area2,area3,area4;
  </code></pre>
  
  <p>any ideas?</p>