Say you’ve got a function:

void f1( int iData){cout << "Hello World";}

When you compile this, you may get the warning about the iData parameter not been referenced. There are three ways to removing this error message:

i) void f1(int){cout << "Hello World";}ii) void f1( int /*iData*/){cout << "Hello World";}iii) void f1(int iData){UNREFERENCED_PARAMETER(iData);cout << "Hello World";}

This UNREFERENCED_PARAMETER is defined in the Winnt.h file, which does nothing.

However, this macro does the work at runtime by adding more statements, so the best options are the first and second methods.