std::weak_ptr<T>::~weak_ptr
來自 cppreference.com
~weak_ptr(); |
(C++11 起) | |
銷燬 weak_ptr
物件。對被管理物件無影響。
[編輯] 示例
此程式顯示了“不打破” std::shared_ptr 迴圈引用的效果。
執行此程式碼
#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; } }; enum class 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 }
輸出
One link is a weak_ptr Leaving... 'A' reclaimed 'B' reclaimed 'C' reclaimed All links are shared pointers Leaving...
[編輯] 參閱
如果沒有更多的 shared_ptr 連結到它,則銷燬所擁有的物件。( std::shared_ptr<T> 的公開成員函式) |