Xcode 11db error thing: Thread 1: EXC_BAD_ACCESS (code=EXC_I386_GPFLT)

Question

I've been trying to write a game in Xcode where a game board is drawn in the terminal using a multidimensional array of type char. The game is supposed to be like a dungeon where there are doors that you can step on and when you do a new room in generated. But sometimes I get this really annoying "(11db)" error thing where one of my lines gets highlighted saying:

"Thread 1: EXC_BAD_ACCESS (code=EXC_I386_GPFLT)"

It's not the first time I've had the (11db) error in Xcode and previously I've been able to fix it but I can't seem to this time. What does that error mean? What I find the most annoying part it that it doesn't happen every time. Sometimes it'll happen as soon as I run the program when the room is created, other times it happens after you go through a door and I've even been able to go without it. Here's the code where it's happening:

    door_x = randomNumber(height - 1, 1);
    door_y = randomNumber(width - 1, 1);

    //Check to see if door location is the same an an enemy or the player
    for (int i = 0; i < enemies.size(); i++){
        while ((door_x == enemies.at(i).getX() && door_y == enemies.at(i).getY()) || (door_x == player->getX() && door_y == player->getY())){
            door_x = randomNumber(height - 1, 1);
            door_y = randomNumber(width - 1, 0);
        }
    }
    room[door_y][door_x] = DOOR;//Place door on map

This error is happening on the last line of the above C++ code. What exactly is wrong and why?

Here's the whole function that creates a new room and my random number function.

int randomNumber(int max, int min){
    int randomNumber = rand() %(max - min) + min;
    return randomNumber;
}

void create_new_room(){
    //Get random room height and room width
    height = randomNumber(settings[0], settings[1]);
    width = randomNumber(settings[2], settings[3]);

    room = new char*[height];
    for (int iter = 0; iter != height; iter++) {
        room[iter] = new char[width];
    }

    for (int i = 0; i < height; i++){
        for (int j = 0; j < width; j++){
            room[i][j] = EMPTY;
        }
    }

    enemies.clear();//Delete every object from the vector

    //Create the enemies
    int numEnemies = randomNumber(settings[4], settings[5]);

    for (int i = 0; i < numEnemies; i++){
        int randomHeight = randomNumber(height, 0);
        int randomWidth = randomNumber(width, 0);
        Enemy *e;//Create pointer to class to allow vector class push back
        e = new Enemy(randomWidth, randomHeight, HEALTH);
        enemies.push_back(*e);
        delete e;//Delete pointer e to free memory and avoid any memory leak.
        room[enemies.at(i).getY()][enemies.at(i).getX()] = ENEMY;//Place enemy on board
    }

    //Create Player
    int player_y = randomNumber(height, 0);
    int player_x = randomNumber(width, 0);
    for (int i = 0; i < enemies.size(); i++){
        while (player_x == enemies.at(i).getX()){
            player_y = randomNumber(height, 0);
            player_x = randomNumber(width, 0);
        }
    }
    player = new Player(player_x, player_y, ATTACK);

    //Place player on board
    room[player->getY()][player->getX()] = PLAYER;

        //Create a door
        door_x = randomNumber(height - 1, 1);
        door_y = randomNumber(width - 1, 1);

        //Check to see if door location is the same an an enemy or the player
        for (int i = 0; i < enemies.size(); i++){
            while ((door_x == enemies.at(i).getX() && door_y == enemies.at(i).getY()) || (door_x == player->getX() && door_y == player->getY())){
                door_x = randomNumber(height - 1, 1);
                door_y = randomNumber(width - 1, 1);
            }
        }
        room[door_y][door_x] = DOOR;//Place door on map
}

Settings[] is an array of setting that I have which reads in values from a text file with user settings for the max and min random values. 0 = Max height 1 = Min height 2 = Max width 3 = Min width 4 = Max enemy 5 = Min enemy

Also I use srand(time(0)) at the top of my main function.

My code is a bit messy but here it is.

1

It's `lldb`, not `11db`. – Emil Laine Sep 27 '15 at 08:40

score 0 · Answer 1 · answered Sep 28 '15 at 16:28

Your code is crashing because you are dereferencing a pointer and ending up in a bad bit of memory. EXC_I386_GPFLT is basically Exception, i386 (your CPU architecture), General Protection Fault, which means that your code is trying to read or write memory that it shouldn't.

Looking at your code, either room is not set (maybe it is NULL still?) or it has been freed already, or door_x or door_y have ended up bigger than you allocated for room (maybe your randomNumber method has a bug?)

You need to print the values for room, door_x, and door_y before your code crashes, and you need to show us the rest of the code so we can see how you've allocated room and how randomNumber works (and how the size of the map is worked out).

And @zenith is right, it's lldb, the LLVM debugger, not 11db. You should read a tutorial on lldb, because you can get huge amounts of information from that prompt.

I've added the create new room function and random number function int my edit above. The create new room is where the room size is made and the actual room array is created. — CharlieFan39, Sep 29 '15 at 00:26

Xcode 11db error thing: Thread 1: EXC_BAD_ACCESS (code=EXC_I386_GPFLT)

1 Answers1