Consider the following code:

#include <iostream>

using namespace std;

class A
{
public:
    A() : test(7) {}
    int test;
    void doSomething() const;
};

void A::doSomething() const
{
    cout << test << endl;
}

int main()
{
    A a;
    a.doSomething();
    return 0;
}

Put a breakpoint in doSomething(), and right-click on 'this' or 'test'. The first action in the menu is Watch Expression "(A)0xaddr" (or ((A)0xaddr).test).

For some reason, this doesn't work for gdb. If I replace A with ::A it works.

Why is it done with the address anyway? Why not just used the name (this, this->test)?