clang: error: linker command failed with exit code 1 (use -v to see invocation)3

Question

I am getting the following error whenever I am making the new project. On changing the Enable Bit Code to No the error is going.

But once I design my main story board i.e. add table view controller and navigation controller to main story board above error is coming again.

I am posting screen shots of the error and my build settings.

Answer 1

I found this Apple Support thread that might help, here is what the answer says:

I'm guessing it was because you have duplicate symbols. It is probably something defined in a header file that should be in a source file

So here are several things that might be causing the issue:

• You are importing a .m file, only import .h files
• If you have an @implementation in a header file, those only go in the implementation file.
• You might have a .m file that is included twice. Leave only one file reference.

You would be able to see them in the Build Phases, see image

• There might be a declaration above the @Interface in the .h file, put it in the @Interface
• Declaring a constant or variable in different .h files with the same name.

• Changing 'No Common Blocks' from Yes to No might help (under Targets->Build Settings->Apple LLVM - Code Generation)

• This could happen also when you have the same @interface in different files with different implementations. For example you have a Player class, in the Player.h/m files and you have a Match class (Match.h/m), and a match is between two player, but not the aforementioned Player.

Player.h

@interface Player : NSObject
@property (nonatomic) NSUInteger _id;
@property (nonatomic, strong) NSString* firstName;
@property (nonatomic, strong) NSString* lastName;
@property (nonatomic, strong) NSString* username;
@end

Match.h

@class Player

@interface Match : NSObject
@property (nonatomic, strong) Player* player1;
@property (nonatomic, strong) Player* player2;
@property (nonatomic) NSUInteger matchId;
@end

@interface Player : NSObject
@property (nonatomic, strong) NSString* nickName;
@property (nonatomic, strong) NSString* point;
@property (nonatomic, strong) NSNumber* lastMove;
@end

In this case the the compiler see two different Player class implementation. You need to refactor the Player class in the Match.h file to MatchPlayer.