EXC_BAD_ACCESS (code=1, address=0x0) when runModalForWindow

objective-c macos exc-bad-access

15,556

Solution 1

the best way to debug EXC_BAD_ACCESS errors is to use NSZombies.

Check out this video for an explanation :

NSZombie keeps all your objects in memory when you are trying to release an object that has already been released, so you get closer to finding your bug. As @Mark H said, it is a memory management issue.

Also you could put an NSLog in your dealloc method to have a better idea of what is getting deallocated when at runtime.

Solution 2

That error will be thrown when the object doesn't exist in memory. I'd start looking for memory management issues. The first would be to make sure you are releasing the ChooseProceduresWindowController after using it.

15,556

Author by

Radu Paise

Updated on June 05, 2022

Comments

Radu Paise almost 2 years
I have a window and a window controller which opens when the user clicks a button. Sometimes I get EXC_BAD_ACCESS(code=1, address=0x0).
```
0x7fff6f2a59e0:  movq   (%rax), %rdi
```
Here is the code:
```
    ChooseProceduresWindowController *chooseProceduresWindowController = [[ChooseProceduresWindowController alloc] initWithWindowNibName:@"ChooseProceduresWindow"];
    [NSApp runModalForWindow:[chooseProceduresWindowController window]];
```
The error appears then runModalForWindow: is called. I don't get this error every time, but I couldn't find a pattern.

Thanks
Radu Paise almost 12 years

I get the error before releasing, when I try to open it in modal.
Mark almost 12 years

Do you open it multiple times and does it ever error out on the first try?
Radu Paise almost 12 years

Yes, I open it multiple times, and No, I didn't get the error on the first try.
Mark almost 12 years

What does the code look like for releasing the allocated memory? Does it always get called?
Radu Paise almost 12 years

[chooseProceduresWindowController release]; - just after the runForModal:
Mark almost 12 years

I might be misunderstanding, but it seems like you are releasing the memory immediately after allocating it. Release the memory when you are done with the modal window.
Nico almost 11 years

@MarkH: runModalForWindow: blocks until the modal event loop has been stopped or aborted (hopefully by the questioner's code in response to an action).
Tim over 10 years

I ran into this error when I tried releasing an alertView twice. (Still a noob at Objective-C)
Nicolas Miari about 10 years

Sometimes an object in the middle of being deallocated throws a "does not respond to selector" exception. And sometimes EXC_BAD_ACCESS is due to reading outside of the bounds of an array (seg fault), if I'm not wrong... But NSZombies is a good measure to start.