Recognition (and processing) of "long double" in C++

I have used VS Community 2015 for a few months but my project needs the "long double" to work. VS treats "long double" exactly like "double". I read that the Intel C++ Compiler would recognise and correctly compile the "long double".

So I downloaded and installed Intel C++ Compiler. Integrated it into VS and activated the Intel C++ Compiler in VS.

Fired off a compile and test and, imagine my disappointment when the "long double" still acted like a "double" as before (with VS C++ compiler).   :(

Is there something else I must do to get a "long double" to work in 80bit as it should? As opposed to a 64bit "double"?

Thanks in anticipation  :)