Debugging with NSZombieEnabled

Question

Hi,

I have been tracing a BAD_ACCESS error using NSZombieEnabled. As error I get returned:

*** -[MyDocument respondsToSelector:]: message sent to deallocated instance 0x2671b0

I do know what this means,however what surprises me is that I don't call this function anywhere, not in MyDocument.m nor in any imported files.To be exact, I don't call this at all in my whole project. The debugger will not go to the actual code that causes the error, but only shows the assembly code, which, when I click on it, gives me and even bigger list of not understandable numbers.

Does anyone have an idea where this weird "respondsToSelector" could come from? Maybe from frameworks I am using? I am really confused.

Thanks for any help!

Answer 1

respondsToSelector: is widely used in frameworks. For instance, if your class is a delegate or data source (highly likely for MyDocument) the delegating object will use it to determine which delegate methods you support.

In general, the way to find out where a problem like this is happening is to set a breakpoint on objc_exception_throw() (Run->Show->Breakpoints, double-click where it says “Double-Click for Symbol”, type objc_exception_throw) and run under the debugger (Build->Build and Debug - Breakpoints On).