Question

I’m writing a game where a MainGameplay class keeps track of whose turn it is by setting an ivar to an enum value:

typedef enum {
  GAME_NOT_STARTED,
  PLAYER_1_TO_MOVE,
  PLAYER_2_TO_MOVE
} WhoseTurnIsIt;

Then the GameBoard class checks whether a move attempt is valid, and calls either turnEnded:(WhoseTurnIsIt)turn or reportTurnFailure:(WhoseTurnIsIt)turn in MainGameplay.m.

I get EXC_BAD_ACCESS as soon as I try to access this returned value back in MainGameplay, in the receiving methods. Seems like I should retain something, but you can’t retain an enum. In the debugger the values are there, so I don’t understand what’s being accessed improperly.

This is the code doing the calling in GameBoard:

-(void)buttonPressed:(id)sender {
  CCArray *kids = [[[CCDirector sharedDirector] runningScene] children];
  if (!mainScene) { // mainScene is an ivar on each the GameBoard's buttons.
    for (CCScene *s in kids) {
      // this looks crazy because the "main" scene is actually a controlling layer that has as a child the main gameplay layer:
      if ([s isKindOfClass:[ControlLayer class]]) {
        self->mainScene = (MainGameplay *)((ControlLayer *) s).gameLayer;
      }
    }
  }

  if (MOVE_NO_ERROR == [self checkMove:mainScene.turn]) {
    [self setMove:mainScene.turn];
    [mainScene turnEnded:mainScene.turn]; // This line and the next are the ones causing the EXC_BAD_ACCESS
  } else [mainScene reportTurnFailure:mainScene.turn]; // This line too.
}

EDIT Functions in mainScene being called go like this:

-(void) reportTurnFailure:(WhoseTurnIsIt)_turn {
  NSLog(@"MainScene still valid"); // This line works fine
  NSLog(@"Bzzzzzt. Player %@, try again", _turn); // This line crashes BUT _turn shows up with a proper value in the debugger.
}

Answer 1

_turn is not an object, but the %@ format specifier says that the argument is an object. Use %i instead.

-(void) reportTurnFailure:(WhoseTurnIsIt)_turn {
  NSLog(@"MainScene still valid"); // This line works fine
  NSLog(@"Bzzzzzt. Player %i, try again", _turn); // This line crashes BUT _turn shows up with a proper value in the debugger.
}