使用STD::函数作为成员函数,它捕获这个“”,并在析构函数之后从复制的lambda访问它

Bang(100500) GetBang prvalue temporary object lifetime

1. [this] will be stored as reference of *this

    class Lambda
    {
    public:
        void operator()() const
        {
            //output
        }

    private:
        Bang& bang;

    public:
        Lambda(Bang& bang) : bang{bang}
        {
        }

    } lambda{*this};
    ...
    m_foo = lambda;

2. RVO b

3. operator() constructor destructor

#include <iostream>
#include <functional>

using namespace std;

class Bang
{
public:
    Bang(int i = 0) : m_val(i)
    {

        std::cout << "Bang(int i = 0) m_val address is " << &m_val << '\n';
        class Lambda
        {
        public:
            void operator()() const
            {

                std::cout << "operator() m_val address is " << &bang.m_val << '\n';
                std::cout << bang.m_val << std::endl;
            }

        private:
            Bang &bang;

        public:
            Lambda(Bang &bang) : bang{bang}
            {
            }

        } lambda{*this};
        m_foo = lambda;

    }

    ~Bang()
    {
        std::cout << "~Bang()\n";
        m_val = -1;
    }

    void Foo()
    {
        m_foo();
    }

private:
    int m_val;
    std::function<void()> m_foo;
};

Bang GetBang()
{
    return Bang(100500);
}

int main()
{
    Bang b;
    b = GetBang();
    b.Foo();
    return 0;
}

live demo

Bang(int i = 0) m_val address is 0x7ffd202c48b0
Bang(int i = 0) m_val address is 0x7ffd202c48e0
~Bang()
operator() m_val address is 0x7ffd202c48e0
-1
~Bang()

• dtor
• m_value

m_foo()

1. @Killzone Kid [bang = *this]
2. [*this] live demo

*this Bang this

#include <iostream>
#include <functional>

class Bang
{
public:
    Bang(int i = 0) : m_val(i)
    {
        m_foo = [bang = *this] { std::cout << bang.m_val << std::endl; };
    }

    ~Bang()
    {
        m_val = -1;
    }

    void Foo()
    {
        m_foo();
    }
private:
    int m_val;
    std::function<void()> m_foo;
};

Bang GetBang()
{
    return Bang(100500);
}

int main()
{
    Bang b;
    b = GetBang();
    b.Foo();
    return 0;
}

https://ideone.com/LUDrBb