How to useFlushRenderingCommands

When I use FlushRenderingCommands,vs printf that there is a error link.was I forget includ some head file?
there is the code

void APlaceActor::Delay(float _DelayTime)
	Sleep(_DelayTime * 1000);

there is the head files

#include "try_004.h"
#include "MyIostream.h"
#include <vector>
#include <windows.h>
#include "PlaceActor.h"

the class name is APlaceActor

thanks,very much

The function exists in RenderingThread.h. So try including RenderingThread.h or RendererInterface.h (As this also includes RenderingThread.h) Then also update your Build.cs to include the RenderCore module

Just to expand for newbies:

The include is:

#include "Runtime/RenderCore/Public/RenderingThread.h"

Then also change {MyProject}.Build.cs:

PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore", "RenderCore" });