在C ++ 14中new和delete仍然有用吗? [英] Are new and delete still useful in C++14?

问题描述

考虑到 make_unique 和 make_shared 的可用性，以及 unique_ptr 和 shared_ptr 析构函数的自动删除功能，在C ++ 14中使用 new 和 delete 的情况(除了支持旧版代码的情况)是什么?

Given availability of make_unique and make_shared, as well as automatic deletion by unique_ptr and shared_ptr destructors, what are the situations (apart from supporting legacy code) for using new and delete in C++14?

推荐答案

尽管在许多情况下，智能指针优于原始指针，但 new /仍然有很多用例在C ++ 14中删除.

While smart pointers are preferable to raw pointers in many cases, there are still lots of use-cases for new/delete in C++14.

如果您需要编写任何需要就地构建的内容，例如:

If you need to write anything that requires in-place construction, for example:

• 内存池
• 分配器
• 带标签的变体
• 二进制消息到缓冲区

您将需要使用展示位置 new ，并且可能需要使用 delete .没办法.

you will need to use placement new and, possibly, delete. No way around that.

对于某些要编写的容器，您可能需要使用原始指针进行存储.

For some containers that you want to write, you may want to use raw pointers for storage.

甚至对于标准智能指针，如果要使用自定义删除器，则仍然需要 new ，因为 make_unique 和 make_shared不允许这样做.

Even for the standard smart pointers, you will still need new if you want to use custom deleters since make_unique and make_shared don't allow for that.

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