Unreal Engine 4.2.1 Development under Windows 8.1 64-bit:
I mistakenly declared a private blueprint implementable event in a C++ class like so:
UCLASS(config=Game)
class ASomeClass
{
...
private:
UFUNCTION(BlueprintImplementableEvent, Category = Foo)
virtual void Bar();
...
}
Obviously this is wrong as blueprint classes derived from ASomeClass won’t be able to call Bar(). But no warnings were issued by the compiler that anything was funky.
When I created a blueprint class BP_SomeClass derived from ASomeClass then tried to use the event in the blueprint event graph, the editor quietly crashdumped in the background, then continued working. The crashdump exception is:
Unhandled exception at 0x00007FF9707B5BF8 (KERNELBASE.dll) in Dump300533408.dmp: 0x00000001: Incorrect function.
The callstack is:
KERNELBASE.dll!00007ff9707b5bf8() Unknown UE4Editor-Core.dll!NewReportEnsure(const wchar_t * ErrorMessage) Line 366 C++ UE4Editor-Core.dll!FDebug::EnsureFailed(const char * Expr, const char * File, int Line, const wchar_t * Msg) Line 300 C++ > UE4Editor-KismetCompiler.dll!FKismetCompilerContext::FinishCompilingFunction(FKismetFunctionContext & Context) Line 1448 C++ UE4Editor-KismetCompiler.dll!FKismetCompilerContext::Compile() Line 3128 C++ UE4Editor-KismetCompiler.dll!FKismet2CompilerModule::CompileBlueprintInner(UBlueprint * Blueprint, bool bPrintResultSuccess, const FKismetCompilerOptions & CompileOptions, FCompilerResultsLog & Results, TArray * ObjLoaded) Line 125 C++ UE4Editor-KismetCompiler.dll!FKismet2CompilerModule::CompileBlueprint(UBlueprint * Blueprint, const FKismetCompilerOptions & CompileOptions, FCompilerResultsLog & Results, FBlueprintCompileReinstancer * ParentReinstancer, TArray * ObjLoaded) Line 159 C++ UE4Editor-UnrealEd.dll!FBlueprintEditorUtils::MarkBlueprintAsStructurallyModified(UBlueprint * Blueprint) Line 1423 C++ UE4Editor-BlueprintGraph.dll!FEdGraphSchemaAction_K2NewNode::PerformAction(UEdGraph * ParentGraph, UEdGraphPin * FromPin, const FVector2D Location, bool bSelectNewNode) Line 154 C++ UE4Editor-BlueprintGraph.dll!FEdGraphSchemaAction_K2AddEvent::PerformAction(UEdGraph * ParentGraph, UEdGraphPin * FromPin, const FVector2D Location, bool bSelectNewNode) Line 432 C++ UE4Editor-BlueprintGraph.dll!FEdGraphSchemaAction_K2NewNode::PerformAction(UEdGraph * ParentGraph, TArray & FromPins, const FVector2D Location, bool bSelectNewNode) Line 187 C++ UE4Editor-Kismet.dll!SBlueprintActionMenu::OnActionSelected(const TArray<TSharedPtr,FDefaultAllocator> & SelectedAction) Line 454 C++ UE4Editor-Kismet.dll!TBaseSPMethodDelegateInstance_OneParam<SBlueprintActionMenu,void,TArray<TSharedPtr,FDefaultAllocator> const & __ptr64,0>::Execute(const TArray<TSharedPtr,FDefaultAllocator> & InParam1) Line 228 C++ UE4Editor-GraphEditor.dll!SGraphActionMenu::HandleSelection(TSharedPtr & InSelectedItem) Line 1151 C++ UE4Editor-GraphEditor.dll!SGraphActionMenu::TryToSpawnActiveSuggestion() Line 759 C++ UE4Editor-GraphEditor.dll!TBaseSPMethodDelegateInstance_TwoParams::Execute(const FText & InParam1, ETextCommit::Type InParam2) Line 228 C++ UE4Editor-GraphEditor.dll!TBaseSPMethodDelegateInstance_TwoParams::ExecuteIfSafe(const FText & InParam1, ETextCommit::Type InParam2) Line 253 C++ UE4Editor-Slate.dll!SSearchBox::HandleTextCommitted(const FText & NewText, ETextCommit::Type CommitType) Line 146 C++ UE4Editor-Slate.dll!TBaseSPMethodDelegateInstance_TwoParams::Execute(const FText & InParam1, ETextCommit::Type InParam2) Line 228 C++ UE4Editor-Slate.dll!TBaseSPMethodDelegateInstance_TwoParams::ExecuteIfSafe(const FText & InParam1, ETextCommit::Type InParam2) Line 253 C++ UE4Editor-Slate.dll!SEditableText::OnEnter() Line 837 C++ UE4Editor-Slate.dll!FTextEditHelper::OnKeyDown(const FGeometry & MyGeometry, const FKeyboardEvent & InKeyboardEvent, ITextEditorWidget & TextEditor) Line 163 C++ UE4Editor-Slate.dll!SEditableText::OnKeyDown(const FGeometry & MyGeometry, const FKeyboardEvent & InKeyboardEvent) Line 1466 C++ UE4Editor-Slate.dll!FSlateApplication::ProcessKeyDownMessage(FKeyboardEvent & InKeyboardEvent) Line 3178 C++ UE4Editor-Slate.dll!FSlateApplication::OnKeyDown(const int KeyCode, const unsigned int CharacterCode, const bool IsRepeat) Line 3116 C++ UE4Editor-Core.dll!FWindowsApplication::ProcessDeferredMessage(const FDeferredWindowsMessage & DeferredMessage) Line 1044 C++ UE4Editor-Core.dll!FWindowsApplication::DeferMessage(TSharedPtr & NativeWindow, HWND__ * InHWnd, unsigned int InMessage, unsigned __int64 InWParam, __int64 InLParam, int MouseX, int MouseY, unsigned int RawInputFlags) Line 1479 C++ UE4Editor-Core.dll!FWindowsApplication::ProcessMessage(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) Line 595 C++ UE4Editor-Core.dll!FWindowsApplication::AppWndProc(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) Line 461 C++ [External Code] UE4Editor-Core.dll!FWindowsPlatformMisc::PumpMessages(bool bFromMainLoop) Line 523 C++ UE4Editor.exe!FEngineLoop::Tick() Line 2073 C++ UE4Editor.exe!GuardedMain(const wchar_t * CmdLine, HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, int nCmdShow) Line 132 C++ UE4Editor.exe!GuardedMainWrapper(const wchar_t * CmdLine, HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, int nCmdShow) Line 125 C++ UE4Editor.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow) Line 207 C++ [External Code]
The ensure that’s failing is in KismetCompiler.cpp:1445:
ensure((Function->FunctionFlags & FUNC_FuncOverrideMatch) == (OverridenFunction->FunctionFlags & FUNC_FuncOverrideMatch));
When I changed the event declaration to be protected instead of private, the crashdump stopped happening. Obviously this is user error, though I imagine this scenario should be caught at compile-time.
Also, please note that CrashReportClient.exe was itself crashing for me with this error:
To fix this, I followed the steps from this AnswerHub question (renaming dbghelp.dll to dbghelp_.dll):
Please let me know if you need any further information. Thanks!