vs2010中的功能错误

Question

I write following in vs2010:

int test() const;

it tell me the const used incorrectly.and said:

Non member function does not allow the use of type qualifier

I wonder why,does it the problem of vs?or how to use such function in vs?

Answer 1

const when applied to a function is only applicable to non-static member functions, not free functions or static member functions.

class A
{
    void f1() const;        // OK
    static void f2() const; // Not OK
};

void f3() const; // Not OK

From the C++ standard:

• 9.3.1 Nonstatic member functions

A non-static member function may be declared const, volatile, or const volatile.

• 9.4.1 Static member functions

A static member function shall not be declared const, volatile, or const volatile.

Answer 2

const in that context means this method will not modify any member variables. If it is not a method of a class (ie it is a free floating function), then it has no meaning.