[Pyobjc-dev] bus error in CGEventTapCreate... found the problem

[Ratko J. <rja...@gm...>]

I am trying to capture some mouse events using CGEventTapCreate and I found
out that the following causes a bus error every time:

eventMask = (1<<kCGEventMouseMoved)
eventTap = CGEventTapCreate(kCGSessionEventTap, kCGHeadInsertEventTap,
0, eventMask, myCGEventCallback)


I've traced it down to two problems, both in Quartz framework in
_callbacks.m in the function m_CGEventTapCreate:

(1) the function expects 5 inputs and yet it tries to assign 6, last one
being "info"... which ends up being an uninitialized pointer. That seems to
cause a bus error further down when it tries to create a tuple of "callback"
and "info":
                  PyObject* real_info = Py_BuildValue("OO", callback, info);

For my purposes, I just changed CGEventTapCreate to accept 6th input when
parsing arguments ("OOOOOO"), as it does in carbon. Not sure if that's the
right approach...


(2) After fixing that, I encountered the next bus error with the line
further down in the same function:
                  CFRelease(retval);
I have no idea why this is crashing but I just commented it out for now. I
am assuming the worst that can happen is a memory leak and considering that
I call this only once, I didn't think it was a big problem.



Also, how does one compile svn trunk properly??? "easy_install pyobjc"
downloads a new version when I want it to compile my modified version. Right
now I have a serious hack... the whole 2.2b2 from easy_install + Quartz
compiled separately from svn (2.2b3).


Some system info:Mac OS X 10.5.7
Apple Python 2.5
built-in PyObjC (also tried PyObjC 2.2b2)


-Ratko