Will a “variableName;” C++ statement be a no-op at all times?

Question

In C++ sometimes a variable will be defined, but not used. Here\'s an example - a function for use with COM_INTERFACE_ENTRY_FUNC_BLIND ATL macro:

HRESULT WIN         


        

Answer 1

Well, it's not really possible to say with 100% certainty without looking at the compiler's source code, but I would be very surprised if this ever generated any code in modern compilers.

At the end of the day, if you're worried about any particular instance then you are always free to look at the generated assembly code.