I have this line of code:

socket_LWIP = std::make_shared<framework::tcpip::socket::SocketLwip>();

where SocketLwip is a structure which has this constructor:

SocketLwip();

defined under the :public section.

I understand that the discussed line of code creates a pointer to this structure, but it is initialized with a () which I don't quite understand. What does () do?

CodePudding user response：

std::make_shared<T>() is a template function. The () is just its parameter list, like with any other function.

The code in question is simply calling std::make_shared<T>(), where T is being set to framework::tcpip::socket::SocketLwip.

std::make_shared<T>() creates a new instance of T, forwarding its own input parameters to T's constructor (which in this case, there aren't any), and returns that new instance wrapped inside of a std::shared_ptr<T> object.

That std::shared_ptr<T> object is then being assigned to the socket_LWIP variable.