Golang is a programming language that has attracted much attention at present, and its concurrency mechanism is one of its features. Channels are a commonly used concurrent communication method in Golang. This article will introduce the usage of golang channels.
1. Introduction to channels
A channel is a pipe used to transmit data and can be used to communicate between different goroutines. Channels are similar to FIFO queues with buffers. Using channels allows different goroutines to synchronize and collaborate to better complete tasks.
Channel is a type in golang. It is defined as:
var 变量名 chan 数据类型
wherechan
is the keyword and the data type can be any legal golang data type. .
2. Channel creation and closing
The creation of the channel is implemented using the make() function, as shown below:
ch := make(chan int) //创建一个int类型的通道
The closing of the channel is completed using the close() function , as shown below:
close(ch) //关闭通道
Since the channel is a reference type, when passing the channel parameter, the address value is passed, and the same is true for operating the channel in the function.
3. Reading and writing of channels
To send data in the channel, use the<-
operator, and to receive data, also use the<-
operator. As shown below:
ch <- data //往通道中写入数据 data := <-ch //从通道中读取数据
The position of<-
operator represents whether to send or receive, and the type of data and the type of channel must be consistent.
If the channel is non-buffered, then the send operation and the receive operation are blocked synchronously, that is, the send operation will block until there is a receiver, and the receive operation will block until there is a sender. If the channel is buffered, send operations will block only if the buffer is full, and receive operations will block only if the buffer is empty.
4. Blocking and non-blocking reading and writing of channels
When reading and writing data in the channel, blocking and non-blocking methods can be used.
The blocking method means that when performing channel read and write operations, if the channel is not ready, the current goroutine will block and wait for the channel to be ready before continuing.
The non-blocking method means that when performing channel read and write operations, if the channel is not ready, the current goroutine will return immediately and continue to perform subsequent operations without blocking.
The code for channel reading and writing using blocking mode is as follows:
ch := make(chan int) data := <-ch //如果通道中没有数据,当前goroutine会阻塞 ch <- data //如果通道已满,当前goroutine会阻塞
The code for channel reading and writing using non-blocking mode is as follows:
select { case data := <-ch: //如果通道中没有数据,会立即返回 case ch <- data: //如果通道已满,会立即返回 default: //默认操作 }
Use select statement The operations of multiple channels can be monitored at the same time. The select statement can prevent loop waiting and avoid deadlock.
5. Summary
The channel in golang is a very effective concurrent communication mechanism. The channel can carry out safe data transmission and collaboration between different goroutines. When using channels, you need to pay attention to the difference between blocking and non-blocking methods. Blocking methods can easily lead to deadlocks when the amount of channel data is large, so developers should use them reasonably.
Through the introduction of this article, I believe you have mastered the basic usage of golang channels. In actual development, rational use of channels can greatly improve the concurrency performance of the program and shorten the running time of the program.
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