Q
When I drag from my application into a Finder window, the system
crashes. I noticed Finder uses a windowKind value of 20 for its windows,
and so does my app. When my app avoids windowKind 20, everything's
hunky-dory. What gives?
A
Through the Drag Manager, Finder has gotten access to the windows in
your app's window list (specifically, by using undocumented calls to
obtain the source window of a drag). If your window's windowKind field
is 20, Finder assumes the window is one of its own (as opposed to a
driver window, whose windowKind would be negative, or a dialog window,
whose windowKind would be 2, etc.). Finder grabs the value in the
window's refCon field and type-casts it to a pointer to a C++ object in
Finder's heap. I think you can see where this is going: when Finder
attempts to dereference the pointer, various crashing behaviors result.
The upshot of this Finder bug is that your application should not use
windowKind values of 20.
[Nov 27 1996]
|
