MSVC direct constructor call extension

Question

In this response, tloveless pointed out that it\'s possible in MSVC to use this->foo::foo(42); for constructor delegation to directly call a con

Answer 1

It is not constructor delegating. Try following code:

#include <iostream>

class C{
public:
    C() { std::cout << "C" << std::endl; }
    ~C() { std::cout << "~C" << std::endl; }
};

struct foo
{
    int m;
    C c;
    foo(int p) : m(p) { std::cout << "foo("<<p<<")\n"; }
    foo()
        : m(0)
    {
        this->foo::foo(42);
        std::cout << "foo(), " << m << "\n";
    }
};

int main()
{
    foo f;
}

According to output field "c" is initialized twice but destroyed only once. As zneak noted, It is similar to new (this) foo(42).