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This article introduces the relevant knowledge of "how to achieve the singleton model on C++". In the operation of actual cases, many people will encounter such a dilemma. Then let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Singleton mode in multithreaded environment

The Instance method is implemented as follows:

How much effort does it take to use this code in a multithreaded environment. As long as you search for [C++], [singleton mode], [multithreading], you will find a large number of articles, so I won't repeat them here.

There are generally several ways mentioned in the article, but the difference is only the question of how to add a lock. Clocked 11 implements the locking operation at the bottom, which ensures that static variables generate multithreaded safety. If you use the static variable to implement the singleton pattern, you don't need to write your own locking operations as you did before:

The header file is not much different, except that the declaration of the static data member is dropped.

In the Instance class method, a static instance object is defined first, and C++ ensures that the initialization process of the object is multi-thread safe. Specifically, when multiple threads call the Instance method, clocking 11 ensures that:

At most, only one instance can be initialized, so

When one initialization process starts, the other cannot enter.

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