test.cpp

class A
{
public:
    A()
    {
        m_gA = this;
    }
    static void test()
    {
        m_gA->m_a += 1;
    }
    void hello()
    {
    }
    static int m_staticA;
    static A* m_gA;
private:
    int m_a;
};

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