title: Undefined symbols for architecture i386: "_OBJC_CLASS_$_Facebook", referenced from: objc-class-ref in AppDelegate.o
body: <p>I have no idea why this error is happening. I have imported the facebook ios sdk static library and I get that error. What could be causing it?</p>
  
  <p>Thanks for any help guys</p>
  
  <p>Undefined symbols for architecture i386:
    "_OBJC_CLASS_$_Facebook", referenced from:
        objc-class-ref in AppDelegate.o
  ld: symbol(s) not found for architecture i386
  clang: error: linker command failed with exit code 1 (use -v to see invocation)</p>
  
  <pre><code>Undefined symbols for architecture i386:
    "_OBJC_CLASS_$_Facebook", referenced from:
        objc-class-ref in AppDelegate.o
  ld: symbol(s) not found for architecture i386
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  </code></pre>