Why does C++ code missing a formal argument name in a function definition compile without warnings?

Question

While getting started with some VS2005-generated MFC code, I noticed it overrode a method with something like this:

void OnDraw(CDC* /*pDC*/)
{
    ...
    /         


        

Answer 1

C++11 N3337 standard draft

http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3337.pdf says it is legal at 8.4.1/6 "Function definitions > In general":

Note: Unused parameters need not be named. For example,

void print(int a, int) {
    std::printf("a = %d\n",a);
}

More precisely, 8.4.1/1 says that the grammar for function definitions is

function-definition:
    attribute-specifier-seqopt decl-specifier-seqopt
    declarator virt-specifier-seqopt function-body

Then if you follow the grammar definitions, e.g. under "Annex A Grammar summary", you will see that the names are optional.