go - 如果我正确使用 channel ，我是否需要使用互斥体？

Question

如果我正确使用 channel ，是否需要使用互斥体来防止并发访问？

Answer 1

如果正确使用 channel ，则不需要互斥锁。在某些情况下，使用互斥锁的解决方案可能更简单。

只需确保在多个 goroutine 尝试访问 channel 变量之前正确初始化保存 channel 值的变量。完成此操作后，访问 channel (例如，向 channel 发送值或从 channel 接收值)在设计上是安全的。

带引用文献的支持文档(强调由我添加):

Spec: Channel types:

A single channel may be used in send statements, receive operations, and calls to the built-in functions cap and len by any number of goroutines without further synchronization. Channels act as first-in-first-out queues. For example, if one goroutine sends values on a channel and a second goroutine receives them, the values are received in the order sent.

Effective Go: Concurrency: Share by communicating

Concurrent programming in many environments is made difficult by the subtleties required to implement correct access to shared variables. Go encourages a different approach in which shared values are passed around on channels and, in fact, never actively shared by separate threads of execution. Only one goroutine has access to the value at any given time. Data races cannot occur, by design. To encourage this way of thinking we have reduced it to a slogan:

Do not communicate by sharing memory; instead, share memory by communicating.

This approach can be taken too far. Reference counts may be best done by putting a mutex around an integer variable, for instance. But as a high-level approach, using channels to control access makes it easier to write clear, correct programs.

这篇文章也很有帮助:The Go Memory Model

同时引用自 sync 的包文档:

Package sync provides basic synchronization primitives such as mutual exclusion locks. Other than the Once and WaitGroup types, most are intended for use by low-level library routines. Higher-level synchronization is better done via channels and communication.