你好，stackoverflow社区，
第一次问。
我正在开发一个原型，用虚幻引擎在虚拟现实中建模CAD数据。我已经设法用我的CAD系统西门子NX，或者更确切地说是API NXOpen来构建我的虚幻项目。
总体来说，API是有效的，我可以调用NXOpen函数，并可以创建基本对象但有些操作会导致崩溃，我猜测这与内存管理有关。我无法理解到底发生了什么。
例如，我有一段代码可以创建一个运行良好的NX块功能。之后，我将需要一个存储在块特征内部的实体对象。访问也可以，但当"bodies"超出范围时，它就会崩溃。访问NX功能中的各种数据时也会发生类似的崩溃。这个伪代码经常触发崩溃：
// 'block' gets created here
if (block) {
std::vector<NXOpen::Body*> bodies = block->GetBodies();
if (bodies.size() > 0) {
NXOpen::Body* body = bodies.front();
}
} // <-- this line crashes
Exception thrown: read access violation.
**flag** was 0xFFFFFFFFFFFFFFFF. occurred
[Inline Frame] UE4Editor-Core.dll!__TBB_machine_cmpswp1(volatile void *) Line 69 C++
> [Inline Frame] UE4Editor-Core.dll!__TBB_TryLockByte(unsigned char &) Line 917 C++
UE4Editor-Core.dll!__TBB_LockByte(unsigned char & flag) Line 924 C++
[Inline Frame] UE4Editor-Core.dll!MallocMutex::scoped_lock::{ctor}(MallocMutex &) Line 66 C++
UE4Editor-Core.dll!rml::internal::Block::freePublicObject(rml::internal::FreeObject * objectToFree) Line 1382 C++
[Inline Frame] UE4Editor-Core.dll!rml::internal::internalPoolFree(rml::internal::MemoryPool * memPool, void *) Line 2571 C++
UE4Editor-Core.dll!rml::internal::internalFree(void * object) Line 2595 C++
UE4Editor-Core.dll!FMemory::Free(void * Original) Line 76 C++
UE4Editor-GestEnUE-Win64-DebugGame.dll!operator delete(void * Ptr, unsigned __int64 Size) Line 6 C++
[External Code]
UE4Editor-GestEnUE-Win64-DebugGame.dll!UNXConnection::AddPointSetsToBody(const FString & name) Line 268 C++
UE4Editor-GestEnUE-Win64-DebugGame.dll!ANXPart::AddCylinder(FVector pos, FVector axis, float height, float diameter, bool WorldSpace) Line 103 C++
UE4Editor-GestEnUE-Win64-DebugGame.dll!ANXPart::execAddCylinder(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 18 C++
UE4Editor-CoreUObject.dll!UFunction::Invoke(UObject * Obj, FFrame & Stack, void * const Z_Param__Result) Line 4643 C++
UE4Editor-CoreUObject.dll!UObject::CallFunction(FFrame & Stack, void * const Z_Param__Result, UFunction * Function) Line 904 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!UObject::ProcessContextOpcode(FFrame & Stack, void * const Z_Param__Result, bool bCanFailSilently) Line 2314 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!UObject::execLetObj(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 2136 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!ProcessLocalScriptFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 974 C++
UE4Editor-CoreUObject.dll!ProcessScriptFunction<void (__cdecl*)(UObject *,FFrame &,void *)>(UObject * Context, UFunction * Function, FFrame & Stack, void * const Z_Param__Result, void(*)(UObject *, FFrame &, void *) ExecFtor) Line 809 C++
UE4Editor-CoreUObject.dll!ProcessLocalFunction(UObject * Context, UFunction * Fn, FFrame & Stack, void * const Z_Param__Result) Line 1033 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!ProcessLocalScriptFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 974 C++
UE4Editor-CoreUObject.dll!ProcessScriptFunction<void (__cdecl*)(UObject *,FFrame &,void *)>(UObject * Context, UFunction * Function, FFrame & Stack, void * const Z_Param__Result, void(*)(UObject *, FFrame &, void *) ExecFtor) Line 809 C++
UE4Editor-CoreUObject.dll!ProcessLocalFunction(UObject * Context, UFunction * Fn, FFrame & Stack, void * const Z_Param__Result) Line 1033 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!UObject::ProcessContextOpcode(FFrame & Stack, void * const Z_Param__Result, bool bCanFailSilently) Line 2314 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!ProcessLocalScriptFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 974 C++
UE4Editor-CoreUObject.dll!ProcessScriptFunction<void (__cdecl*)(UObject *,FFrame &,void *)>(UObject * Context, UFunction * Function, FFrame & Stack, void * const Z_Param__Result, void(*)(UObject *, FFrame &, void *) ExecFtor) Line 809 C++
UE4Editor-CoreUObject.dll!ProcessLocalFunction(UObject * Context, UFunction * Fn, FFrame & Stack, void * const Z_Param__Result) Line 1033 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!ProcessLocalScriptFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 974 C++
UE4Editor-CoreUObject.dll!UObject::ProcessInternal(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 1058 C++
UE4Editor-CoreUObject.dll!UFunction::Invoke(UObject * Obj, FFrame & Stack, void * const Z_Param__Result) Line 4643 C++
UE4Editor-CoreUObject.dll!UObject::ProcessEvent(UFunction * Function, void * Parms) Line 1464 C++
UE4Editor-Engine.dll!AActor::ProcessEvent(UFunction * Function, void * Parameters) Line 769 C++
UE4Editor-GestEnUE-Win64-DebugGame.dll!ABuilderBase::commit() Line 37 C++
UE4Editor-GestEnUE-Win64-DebugGame.dll!AGestEnLeapPawn::Tick(float DeltaTime) Line 138 C++
UE4Editor-Engine.dll!AActor::TickActor(float DeltaSeconds, ELevelTick TickType, FActorTickFunction & ThisTickFunction) Line 970 C++
UE4Editor-Engine.dll!FActorTickFunction::ExecuteTick(float DeltaTime, ELevelTick TickType, ENamedThreads::Type CurrentThread, const TRefCountPtr<FGraphEvent> & MyCompletionGraphEvent) Line 164 C++
[Inline Frame] UE4Editor-Engine.dll!FTickFunctionTask::DoTask(ENamedThreads::Type) Line 285 C++
UE4Editor-Engine.dll!TGraphTask<FTickFunctionTask>::ExecuteTask(TArray<FBaseGraphTask *,FDefaultAllocator> & NewTasks, ENamedThreads::Type CurrentThread) Line 842 C++
[Inline Frame] UE4Editor-Core.dll!FBaseGraphTask::Execute(TArray<FBaseGraphTask *,FDefaultAllocator> & CurrentThread, ENamedThreads::Type) Line 511 C++
UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksNamedThread(int QueueIndex, bool bAllowStall) Line 686 C++
UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksUntilQuit(int QueueIndex) Line 582 C++
[Inline Frame] UE4Editor-Core.dll!FTaskGraphImplementation::ProcessThreadUntilRequestReturn(ENamedThreads::Type) Line 1406 C++
UE4Editor-Core.dll!FTaskGraphImplementation::WaitUntilTasksComplete(const TArray<TRefCountPtr<FGraphEvent>,TInlineAllocator<4,FDefaultAllocator> > & Tasks, ENamedThreads::Type CurrentThreadIfKnown) Line 1457 C++
UE4Editor-Engine.dll!FTickTaskSequencer::ReleaseTickGroup(ETickingGroup WorldTickGroup, bool bBlockTillComplete) Line 557 C++
UE4Editor-Engine.dll!FTickTaskManager::RunTickGroup(ETickingGroup Group, bool bBlockTillComplete) Line 1505 C++
UE4Editor-Engine.dll!UWorld::RunTickGroup(ETickingGroup Group, bool bBlockTillComplete) Line 789 C++
UE4Editor-Engine.dll!UWorld::Tick(ELevelTick TickType, float DeltaSeconds) Line 1568 C++
UE4Editor-UnrealEd.dll!UEditorEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 1618 C++
UE4Editor-UnrealEd.dll!UUnrealEdEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 403 C++
UE4Editor-Win64-DebugGame.exe!FEngineLoop::Tick() Line 3967 C++
[Inline Frame] UE4Editor-Win64-DebugGame.exe!EngineTick() Line 62 C++
UE4Editor-Win64-DebugGame.exe!GuardedMain(const wchar_t * CmdLine, HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, int nCmdShow) Line 168 C++
UE4Editor-Win64-DebugGame.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow) Line 261 C++
如果我正确理解调用堆栈，则在删除对象时会发生错误。但为什么会出现这样的问题呢？可能是Unreal和NX第三方库都试图管理内存吗？
有人知道是什么导致了这些崩溃，甚至知道如何解决吗？如有必要，我很乐意提供更多信息。
问候，LaRanaRica
我发现在使用NXOpen时，使用调试运行库通常会导致内存错误。您可以使用链接器设置/MD(inds而不是/MDd(来更改此设置。
我知道这很晚了，但我有一个比在发布模式而不是调试模式下构建更好的解决方案，因为我以前遇到过很多次这个问题，并使用相同的简单解决方案解决了它。
我不知道为什么NX Open C++会出现这种情况，但只有当同时使用std::vector(一些NX Open C++API返回(和调试模式时才会出现这种情况。您可以通过在所有#includes:之前将这一行添加到C++源文件的顶部来修复它
#define _ITERATOR_DEBUG_LEVEL 0