Using pointer-to-member functions with std::shared_ptr

Question

I'm struggling with this piece of code:

typedef shared_ptr<node <T>> (node<T>::*son_getter)();
    son_getter get_son[] = {&node<T>::getLeftSon, &node<T>::getRightSon};

insert = node->*get_son[index]();

I get a compilation error:

error: must use ‘.*’ or ‘->*’ to call pointer-to-member function in ‘get_son[index] (...)’, e.g. ‘(... ->* get_son[index]) (...)’
 insert = node->*get_son[index]();

Where node is shared_ptr<node<T>> just as insert is.

I've tried everything I could guess and still no idea what's going on.

Answer 1

First of all, a function call operator () has a higher priority than ->*, as such, you need to add parenthesis to enforce the desired evaluation order. Additionally, node is a smart pointer, while the pointer to member function refers to the type stored in that shared pointer.

Having said that, you need to use one of the below alternatives:

(*node.*get_son[index])();

(&*node->*get_son[index])(); // or std::addressof(*node)->*

(node.get()->*get_son[index])();