Log function names automatically with __FUNCTIONW__

Logging automatically generated function string literals

Underneath are what certain macros (or compiler-generated fields) automatically expand to inside the scope of void AMyActor::TestFunction(AActor* UselessArgument):

Macro / field	Expands to
`__func__`	`TestFunction`
`__FUNCTION__`	`AMyActor::TestFunction`
`__FUNCTIONW__`	`AMyActor::TestFunction`
`__FUNCSIG__`	`void AMyActor::TestFunction(AActor* UselessArgument)`
`__PRETTY_FUNCTION__`	`void AMyActor::TestFunction(AActor* UselessArgument)`

Usage example (with output commented)

void AMyActor::TestFunction(AActor* UselessArgument)
{
    // TestFunction
    UE_LOG(LogTemp, Warning, TEXT("%s"), ANSI_TO_TCHAR(__func__));

    // AMyActor::TestFunction
    UE_LOG(LogTemp, Warning, TEXT("%s"), TEXT(__FUNCTION__));

    // AMyActor::TestFunction
    UE_LOG(LogTemp, Warning, TEXT("%s"), __FUNCTIONW__);

    // void AMyActor::TestFunction(AActor* UselessArgument)
    UE_LOG(LogTemp, Warning, TEXT("%s"), TEXT(__FUNCSIG__));

    // May not compile. Use __FUNCSIG__
    // void AMyActor::TestFunction(AActor* UselessArgument)
    UE_LOG(LogTemp, Warning, TEXT("%s"), TEXT(__PRETTY_FUNCTION__));
}

Notes:

__PRETTY_FUNCTION__ may not compile. Use __FUNCSIG__ instead.

If you’re using __FUNCSIG__ and get this:

void __cdecl AInteractableActor::BeginPlay(void)

There's a hack to remove the "__cdecl" part:

{
	FString Funcsig = __FUNCSIG__;
	int32 Index = Funcsig.Find("__cdecl");
	if (Index != -1)
	{
		Funcsig.RemoveAt(Index, 8);
	}	
	UE_LOG(LogTemp, Warning, TEXT("%s"), *Funcsig);
}