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This article mainly explains "how to understand C++ multithreaded programming". The content of the article is simple and clear, and it is easy to learn and understand. let's study and learn "how to understand C++ multithreaded programming".

Catalogue

C++ multithreading

1. Concept

1.1 concept

two。 Commonly used API

1.thread

two。 Mutex mutex

3. Suspend and wake up

3. Application scenario

3.1 functions executed once by call_once

3.2 condition_variable conditional lock

3.3 future gets the calculation results of the thread

3.4 how the promise main thread sends data to other threads

3.5 future.share () shared state among multithreads

3.6 Thread packaged_task

3.7 time constraint

4. Windows multithreading

4.1 Windows creation thread

4.2 Windows mutex

4.3 Windows suspend and Wake up Thread

Summary

C++ multithreading 1. Concept 1.1 concept

Process: an application that runs in memory. Each process has its own independent memory space, and a process can have multiple threads. For example, in a Windows system, a running xx.exe is a process.

Thread: an execution task (control unit) in a process that is responsible for the execution of programs in the current process. A process has at least one thread, a process can run multiple threads, and multiple threads can share data. Unlike a process, multiple threads of the same kind share the heap and method area resources of the process, but each thread has its own program counter, virtual machine stack and local method stack, so the system generates a thread. Or when switching between threads, the burden is much less than the process, and because of this, threads are also called lightweight processes.

Concurrency: concurrency means that two or more independent activities occur at the same time. Concurrency can be seen everywhere in life, such as listening to music while running, tapping the keyboard while watching the computer monitor, and so on. Multiple operations can be handled alternately in the same period of time, emphasizing that they occur alternately in the same period of time.

Parallel: multiple operations are processed at the same time, emphasizing that the same time point occurs at the same time.

two。 Commonly used API

Header file # include

1.threadAPI description Note: thread.join () join the thread (will block the main thread and simulate the synchronization operation)

Thread.detach () joins the thread (does not block the main thread and simulates asynchronous operations)

Whether thread.joinable () can join the thread or not, returns bool

Thread.get_id () gets the thread's ID

Thread.hardware_concurrency () gets the number of hardware concurrency

Thread.swap () swap thread

Thread.native_handle () gets the native handle, which is the return value of CreateThread in windows multithreading. Using this handle, the thread can be suspended and awakened.

Test the code:

Void threadFunc01 () {cout

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