title: ZXing Library: Errors in iOS: private field 'cached_y_' is not used
body: <p>I am currently trying to use the ZXing Library for an iOS Project. However I can't even get the sample Projects to work.</p>
  
  <p>The ScanTest Project, as well as the ones that I created myself throw the following error in the BinaryBitmap.cpp file.</p>
  
  <pre><code>In file included from /Volumes/Macintosh HD/Users/Tim/Downloads/zxing-2.1/iphone/ZXingWidget/../../cpp/core/src/zxing/BinaryBitmap.cpp:20:
  ../../cpp/core/src/zxing/BinaryBitmap.h:33:7: error: private field 'cached_y_' is not used [-Werror,-Wunused-private-field]
              int cached_y_;
                  ^
  1 error generated.
  </code></pre>
  
  <p>I searched on Google and Stackoverflow, but have not found a solution for the problem.</p>
  
  <p>I have tried it with both the current stable release of XCode and the beta.</p>
  
  <p>I don't know if anybody else has got this problem too, but any help would be greatly appreciated.</p>