Odd EXC_BAD_ACCESS error and general leaks and beginners trouble

Question

Hi,
I am new to apple programming and thought I'd get into that and opengl programming by creating a small utility to display images.
I've stumbled upon memory leaks, however. The "leaks" CLI utility mentions lots of leaks, but I'm not sure I can trust that.
The xcode project can be seen at http://elendil.qeep.dk/code/opengl_imageviewer/ and the main file at http://elendil.qeep.dk/code/opengl_imageviewer/main.cpp. An archive can also be found at http://elendil.qeep.dk/code/opengl_imageviewer.zip for the interested.
I have two problems. First of all, upon calling NavDialogRun(ref) in getFileURLRef() (line 86) the xcode run log gives me lots of "2007-08-06 02:10:17.977 opengl_imageviewer[12047] * _NSAutoreleaseNoPool(): Object 0x37bba0 of class NSCFDictionary autoreleased with no pool in place - just leaking" messages that I do not understand at all. I reckon this is the main culprit.
Secondly if I call the glPixelStorei() functions in line 129 and 130 the gdb debugger pops up with "EXCBADACCESS". Commenting out these lines makes the code seemingly work. I doubt these two commands are the base of the problem, however.
I'd really appreciate any help. Thanks.
Sincerely,
-Kenneth

Answer 1

It is prefectly understandable. I was working on a little app to use MacOS X's built-in spellchecker as a replacement for ispell. I had the exact same problem. The classes I had to use seemed completely independent. But they just wouldn't work until all the Cocoa runtime had been initialized. It is hard to tell which parts will behave that way. Usually, it is the higher level, OS or user interaction classes. The base core foundation classes or low-level Cocoa (NSAutoReleasePool, for example) will always work.
MacOS X is also a confusing beast. While Cocoa is the best and easiest way to get most things done, there are some things that need Carbon. Those navigation dialogs, for example, don't exist in Cocoa as far as I can tell. You must use Carbon. Yet, they seem to use Cocoa underneath. There are several other MacOS X subsystems that are the same way.
As for C++ vs. Obj-C, that has to be a purely personal decision. Like yourself, I spent many years learning and using C++. That was a huge investment and I would like to get something out of it. But, as difficult as it is to say it, I must admit that lately I have been more productive using Cocoa and ObjC than I could have been using C++, even though I know C++ backwards and forwards.
I make it a point to use Objective-C++ (using .mm files instead of .m). In theory I can now use my Carbon-aware auto_ptr, but I usually end up not even using that. At least I can declare my variables where I want.