After I integrate ZBar Sdk into my project, my xcode 5-DP starts showing below warning:
"ld: warning: linking ObjC for iOS Simulator, but object file (/Documents/Projects/Project/Utility/ZBarSDK/libzbar.a(ZBarReaderViewController.o)) was compiled for MacOSX "
I skirted the error by changing the "Build Active Architecture Only" to YES, not only for Debug but for Release too... At least for now, this saved me.