linker command failed with exit code 1 after I upgrade to Xcode 7

Question

After I upgraded to El Capitan and Xcode 7, I cannot build my app. I keep getting duplicate symbols on all of my global variables. Please help.

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//Global.h
#ifndef Global_h
#define Global_h

extern NSInteger pickerConstantOne, pickerConstantTwo,numberOfDays, monthOfToday;

NSInteger pickerConstantOne, pickerConstantTwo,numberOfDays, monthOfToday;

#endif /* Global_h */

Answer 1

You have misdeclared those variables; remove this statement from the header:

NSInteger pickerConstantOne, pickerConstantTwo,numberOfDays, monthOfToday;

and move it into a .m file.

You should also review exactly why you are using global variables in the first place as you certainly don't need to be.