std::vector 是否使用 push_back 复制对象?

问题描述

在对 valgrind 进行大量调查后，我得出的结论是 std::vector 制作了一个您想要 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.

真的是这样吗?一个向量不能在没有副本的情况下保留对象的引用或指针?！

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

谢谢

推荐答案

是的，std::vector::push_back() 创建参数的副本并将其存储在向量中.如果您想在向量中存储指向对象的指针，请创建一个 std::vector 而不是 std::vector.

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在向量持有对它们的引用时保持有效(使用 RAII 惯用语的智能指针解决了问题).

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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