c++ - 如何在lambda中访问捕获的此指针的 `typeid`？

Question

我有以下代码:

#include <iostream>

class Bobo
{public:
    int member;
    void function()
    {
        auto lambda = [this]() { std::cout << member << '\n'; };
        auto lambda2 = [this]() { std::cout << typeid(*this).name() << '\n'; };
        lambda();
        lambda2();
    }
};

int main()
{
    Bobo bobo;
    bobo.function();
}

std::cout行<< typeid(* this).name();在lambda2()中可以打印出:

class <lambda_49422032c40f80b55ca1d0ebc98f567f>

但是，如何访问已捕获的“this”指针，以便typeid运算符可以返回类型类Bobo？

编辑:我得到的结果是在Visual Studio Community 2019中编译此代码。

Answer 1

这似乎是VS的错误；在lambda中确定this指针的类型时:

For the purpose of name lookup, determining the type and value of the this pointer and for accessing non-static class members, the body of the closure type's function call operator is considered in the context of the lambda-expression.

struct X {
    int x, y;
    int operator()(int);
    void f()
    {
        // the context of the following lambda is the member function X::f
        [=]()->int
        {
            return operator()(this->x + y); // X::operator()(this->x + (*this).y)
                                            // this has type X*
        };
    }
};

因此 this的类型应在lambda中为 Bobo*。