How to pass a variable by reference in C++ function called in Blueprints

By default, when a non-const reference is specified in a function, it will be treated by Blueprints as an output parameter:

UFUNCTION(BlueprintCallable)
static void RemoveDots(FString& String)
{
	String.ReplaceInline(TEXT("."), TEXT(" "));
}

There is a macro called UPARAM which is not widely used, but can control the behavior of parameters specified in UFUNCTIONs. In particular, it can change the behavior of passing non-const references by specifying a ref meta:

UFUNCTION(BlueprintCallable)
static void RemoveDots(UPARAM(ref) FString& String)
{
	String.ReplaceInline(TEXT("."), TEXT(" "));
}

This actually works similarly as specifying “Pass-by-reference” in a Blueprint-only function