What is

I have this function call which I don't understand its syntax:

FunctionName<IS_SET_AUTO_REFERENCE>(Parameter1, Parameter2,Parameter3);

IS_SET_AUTO_REFERENCE sounds to be a Boolean but it is Not used anywhere neither defined.

Is this c++11 or c++? Is it related to the language? Google search shows other programmers using it with OpenCV but I still don't see What does IS_SET_AUTO_REFERENCE exactly serve here and how?