是std :: vector使用push_back复制对象吗？ [英] Is std::vector copying the objects with a push_back?

问题描述

经过对valgrind的大量调查，我得出结论，std :: vector创建了一个要push_back的对象的副本。

After a lot of investigations with valgrind, I've made the conclusion that std::vector makes a copy of an object you want to push_back.

真的 ？向量不能保存引用或没有副本的对象的指针？

Is that really true ? A vector cannot keep a reference or a pointer of an object without a copy ?!

感谢

推荐答案

是， std :: vector< T> :: push_back（）创建参数的副本并将其存储在向量中。如果你想存储指向你的向量中的对象的指针，创建 std :: vector< whatever *> 而不是 std :: vector< whatever> ; 。

Yes, std::vector<T>::push_back() creates a copy of the argument and stores it in the vector. If you want to store pointers to objects in your vector, create a std::vector<whatever*> instead of std::vector<whatever>.

但是，您需要确保指针引用的对象保持有效，而向量保存对它们的引用（使用RAII成语的智能指针解决问题） 。

However, you need to make sure that the objects referenced by the pointers remain valid while the vector holds a reference to them (smart pointers utilizing the RAII idiom solve the problem).

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