std::weak_ptr<T>::~weak_ptr
From cppreference.com
~weak_ptr(); | (since C++11) | |
Destroys the weak_ptr object. Results in no effect to the managed object.
[edit]Example
The program shows the effect of "non-breaking" the cycle of std::shared_ptrs.
Run this code
#include <iostream>#include <memory>#include <variant> class Node {char id;std::variant<std::weak_ptr<Node>, std::shared_ptr<Node>> ptr;public: Node(char id): id{id}{} ~Node(){std::cout<<" '"<< id <<"' reclaimed\n";}/*...*/void assign(std::weak_ptr<Node> p){ ptr = p;}void assign(std::shared_ptr<Node> p){ ptr = p;}}; enumclass shared { all, some }; void test_cyclic_graph(const shared x){auto A =std::make_shared<Node>('A');auto B =std::make_shared<Node>('B');auto C =std::make_shared<Node>('C'); A->assign(B); B->assign(C); if(shared::all== x){ C->assign(A);std::cout<<"All links are shared pointers";}else{ C->assign(std::weak_ptr<Node>(A));std::cout<<"One link is a weak_ptr";}/*...*/std::cout<<"\nLeaving...\n";} int main(){ test_cyclic_graph(shared::some); test_cyclic_graph(shared::all);// produces a memory leak}
Output:
One link is a weak_ptr Leaving... 'A' reclaimed 'B' reclaimed 'C' reclaimed All links are shared pointers Leaving...
[edit]See also
destructs the owned object if no more shared_ptrs link to it (public member function of std::shared_ptr<T>) |
