How to use wxTreeItemData without crashing upon deletion - c++

Question

I'm using wxWidgets, and I have a wxTreeCtrl set up with a root and a single child. I'm setting client data on the child and it works fine until the window closes, at which point I get a bus error, which I'm assuming is coming from wxWidgets attempting to delete my client data.
Here's my client data struct:
struct MapPtrCtr {
Map* map;
MapPtrCtr(Map* map) : map(map) {}
};
Here's how I set the client data (note that here, map is std::shared_ptr<Map>):
wxTreeItemId childNode = mapTree->AppendItem(node, map->getTitle());
mapTree->SetItemData(childNode, (wxTreeItemData*) new MapPtrCtr(map.get()));
Here's the error I get:
Process: AromatherapyMapEditor [43832]
Path: /Users/USER/*/AromatherapyMapEditor
Identifier: AromatherapyMapEditor
Version: 0
Code Type: X86-64 (Native)
Parent Process: bash [805]
Responsible: Terminal [798]
User ID: 501
Date/Time: 2015-03-16 13:38:02.964 -0400
OS Version: Mac OS X 10.10.1 (14B25)
Report Version: 11
Anonymous UUID: 3887BB6D-7783-EBA5-C86C-FACE1C21094E
Sleep/Wake UUID: 9C9670EA-BBC7-4046-B544-F1CE3F184398
Time Awake Since Boot: 84000 seconds
Time Since Wake: 12000 seconds
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x00007fb920f1ae80
VM Regions Near 0x7fb920f1ae80:
MALLOC_TINY 00007fb920d00000-00007fb920f00000 [ 2048K] rw-/rwx SM=PRV
--> MALLOC_TINY 00007fb920f00000-00007fb921000000 [ 1024K] rw-/rwx SM=COW
MALLOC_SMALL 00007fb921000000-00007fb921800000 [ 8192K] rw-/rwx SM=COW
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 ??? 0x00007fb920f1ae80 0 + 140433098387072
1 libwx_osx_cocoau_core-3.0.dylib 0x00000001075f6a26 wxGenericTreeItem::DeleteChildren(wxGenericTreeCtrl*) + 94
2 libwx_osx_cocoau_core-3.0.dylib 0x00000001075fabe2 wxGenericTreeCtrl::Delete(wxTreeItemId const&) + 264
3 libwx_osx_cocoau_core-3.0.dylib 0x00000001075fac64 wxGenericTreeCtrl::DeleteAllItems() + 40
4 libwx_osx_cocoau_core-3.0.dylib 0x00000001075f925c wxGenericTreeCtrl::~wxGenericTreeCtrl() + 102
5 libwx_osx_cocoau_core-3.0.dylib 0x000000010759f96b wxTreeCtrl::~wxTreeCtrl() + 15
6 libwx_osx_cocoau_core-3.0.dylib 0x00000001075a5da0 wxWindowBase::Destroy() + 40
7 libwx_osx_cocoau_core-3.0.dylib 0x00000001075a5e96 wxWindowBase::DestroyChildren() + 20
8 libwx_osx_cocoau_core-3.0.dylib 0x0000000107438d79 wxWindow::~wxWindow() + 215
9 libwx_osx_cocoau_core-3.0.dylib 0x00000001075effeb wxSplitterWindow::~wxSplitterWindow() + 15
10 libwx_osx_cocoau_core-3.0.dylib 0x00000001075a5da0 wxWindowBase::Destroy() + 40
11 libwx_osx_cocoau_core-3.0.dylib 0x00000001075a5e96 wxWindowBase::DestroyChildren() + 20
12 libwx_osx_cocoau_core-3.0.dylib 0x0000000107435121 wxNonOwnedWindow::~wxNonOwnedWindow() + 45
13 AromatherapyMapEditor 0x000000010739f913 MapeditFrame::~MapeditFrame() + 259 (frame.h:24)
14 AromatherapyMapEditor 0x000000010739e1f5 MapeditFrame::~MapeditFrame() + 21 (frame.h:24)
15 AromatherapyMapEditor 0x000000010739e219 MapeditFrame::~MapeditFrame() + 25 (frame.h:24)
16 libwx_baseu-3.0.dylib 0x000000010795ec72 wxAppConsoleBase::DeletePendingObjects() + 74
17 libwx_baseu-3.0.dylib 0x000000010795ebd3 wxAppConsoleBase::ProcessIdle() + 85
18 libwx_osx_cocoau_core-3.0.dylib 0x00000001074dcef6 wxAppBase::ProcessIdle() + 22
19 libwx_osx_cocoau_core-3.0.dylib 0x000000010746be5a wxApp::ProcessIdle() + 26
20 libwx_baseu-3.0.dylib 0x0000000107984faa wxEventLoopBase::ProcessIdle() + 28
21 libwx_baseu-3.0.dylib 0x0000000107a0d661 wxCFEventLoop::CommonModeObserverCallBack(__CFRunLoopObserver*, int) + 69
22 com.apple.CoreFoundation 0x00007fff8db02d87 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
23 com.apple.CoreFoundation 0x00007fff8db02ce0 __CFRunLoopDoObservers + 368
24 com.apple.CoreFoundation 0x00007fff8daf4f1a __CFRunLoopRun + 1178
25 com.apple.CoreFoundation 0x00007fff8daf4838 CFRunLoopRunSpecific + 296
26 com.apple.HIToolbox 0x00007fff926dd43f RunCurrentEventLoopInMode + 235
27 com.apple.HIToolbox 0x00007fff926dd1ba ReceiveNextEventCommon + 431
28 com.apple.HIToolbox 0x00007fff926dcffb _BlockUntilNextEventMatchingListInModeWithFilter + 71
29 com.apple.AppKit 0x00007fff8b6906d1 _DPSNextEvent + 964
30 com.apple.AppKit 0x00007fff8b68fe80 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 194
31 com.apple.AppKit 0x00007fff8b683e23 -[NSApplication run] + 594
32 libwx_osx_cocoau_core-3.0.dylib 0x00000001074bdd8c wxGUIEventLoop::OSXDoRun() + 106
33 libwx_baseu-3.0.dylib 0x0000000107a0db35 wxCFEventLoop::DoRun() + 39
34 libwx_baseu-3.0.dylib 0x0000000107984ed8 wxEventLoopBase::Run() + 88
35 libwx_baseu-3.0.dylib 0x000000010795ea04 wxAppConsoleBase::MainLoop() + 128
36 libwx_osx_cocoau_core-3.0.dylib 0x000000010746bea8 wxApp::OnRun() + 26
37 libwx_baseu-3.0.dylib 0x00000001079b33ae wxEntry(int&, wchar_t**) + 71
38 AromatherapyMapEditor 0x000000010738d706 main + 38 (main.cpp:15)
39 libdyld.dylib 0x00007fff916bf5c9 start + 1
Any suggestions? I'm not sure how to properly use wxTreeItemData because there's very little documentation on it. The docs say to make sure to initialize the struct with new, and I do, so I'm not sure why there's a problem.

Answer 1

That was quick. I figured out how to properly use wxTreeItemData: you have to subclass it, not just cast to it. The following client data class works:
class MapPtrCtr : public wxTreeItemData {
public:
Map* map;
MapPtrCtr(Map* map) : map(map) {}
};