Linker command failed with exit code 1 (duplicate symbol)

Question

I developing a game in Unity and I have used Admob, Facebook and GameCenter in it. It was working fine on iOS until I have added the OpenIAB for in-app purchase, though it works

Answer 1

I have recently face the same issue. I know Umer Azeem got the answer but to help someone else who may suffer from the same issue I was in.
According to my application flow I am using printer related third party class to print. To use that I have created object of that class in both of my files ImagePrintViewController and PrintResultViewController separately and passed required data to it.

In my scenario I am getting same error with variable name like _printerSetup in two of my files/Library/Developer/Xcode/DerivedData/../x86_64/ImagePrintViewController.o and /Library/Developer/Xcode/DerivedData/../x86_64/PrintResultViewController.o.
I have search in both of my file for the above variable name. But I couldn't find that.

After searching long on this I got a idea to delete reference of my second file i.e. BRPrintResultViewController.h and BRPrintResultViewController.m after merging code in my first file.

With this I found my solution and my code runs fine after this.