1、什麽是線程

在傳統操作系統中，每個進程有一個地址空間，而且默認就有一個控制線程
進程只是用來把資源集中到一起（進程只是一個資源單位，或者說資源集合）
線程才是cpu上的執行單位。

多線程（即多個控制線程）的概念是，在一個進程中存在多個線程，多個線程共享該進程的地址空間，　

相當於一個車間內有多條流水線，都共用一個車間的資源。例如，北京地鐵與上海地鐵是不同的進程，

而北京地鐵裏的13號線是一個線程，北京地鐵所有的線路共享北京地鐵所有的資源，比如所有的乘客可以被所有線路拉。

2、多線程應用舉例

3、開啟進程的兩種方式：threading模塊

• multiprocess模塊的完全模仿了threading模塊的接口，二者在使用層面，有很大的相似性，因而不再詳細介紹

4、線程與進程的區別

1. Threads share the address space of the process that created it; processes have their own address space.
2. Threads have direct access to the data segment of its process; processes have their own copy of the data segment of the parent process.
3. Threads can directly communicate with other threads of its process; processes must use interprocess communication to communicate with sibling processes.
4. New threads are easily created; new processes require duplication of the parent process.
5. Threads can exercise considerable control over threads of the same process; processes can only exercise control over child processes.
6. Changes to the main thread (cancellation, priority change, etc.) may affect the behavior of the other threads of the process; changes to the parent process does not affect child processes.

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5-[多線程]-線程理論