Why comment parameter names rather than leave it as it is

Question

Sometimes I see code like this:

LRESULT OnPaint(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/)

Why comment pa

Answer 1

I think there are/were some compilers which issued a 'argument not used' warning when, well, the arguments were not used.

Especially in message handler functions like the one you showed, the arguments are often not necessary to perform the task. So by commenting the argument names out, you could get rid of the warnings.

On the other hand, if you later want to use some of the arguments, it's useful to have the names at hand, so commenting out is easier than just deleting the names.