[MSW] Crash in wxGDIPlusRendererModule

[markusj]

To reproduce:
- start unmodified "drawing" sample
- file menu -> Graphics screen
- close application

Crashes when deleting the new 'gs_drawTextStringFormat'.

[vadz]

Sorry, I don't see this. Please try rebuilding all and testing again. If it still happens, could you please provide a full stack trace? What is the value of gs_drawTextStringFormat when it's being deleted?

[markusj]

Did a full rebuild, still happens. But only under XP, not Windows 7.

I don't know if it's relevant, but i noticed that the module "wxGdiPlusModule" is destroyed first, this one unloads GDI32.DLL. The crash then happens later when "wxGDIPlusRendererModule" is destroyed.

Callstack attached.

[vadz]

Thanks for your remark, I do think it's relevant and I believe the following patch should fix the problem:

src/msw/graphics.cpp

@@ -2283 +2283 @@
 class wxGDIPlusRendererModule : public wxModule
 {
 public:
+    wxGDIPlusRendererModule()
+    {
+        // We must be uninitialized before GDI+ DLL itself is unloaded.
+        AddDependency("wxGdiPlusModule");
+    }
+
     virtual bool OnInit() { return true; }
     virtual void OnExit()
     {

Does it?

[markusj]

Yes, perfect. Thanks for the fast response, much appreciated.

[markusj]

Just out of curiosity: Do you have an explanation why this didn't crash under Windows 7?

[vadz]

The module (un)loading order may have been different or, more likely, something else holds on GDI+ DLL under Windows 7 so it wasn't really unloaded when we did it.

[VZ]

(In [72717]) Ensure the correct cleanup order for GDI+-related modules in wxMSW.

GDI+ DLL could be unloaded by wxGdiPlusModule before wxGDIPlusRendererModule::
OnExit() was called, resulting in a crash when trying to call a GDI+ function
from the latter.

Fix this by adding a correct dependency between the modules.

Closes #14769.