How to close channel in golang

Golang is an efficient, strongly typed, concurrency-supported programming language. Channel, as one of Golang's concurrent programming mechanisms, plays a very important role. When using channels, in order to ensure the robustness and performance of the program, it is very important to use the channel closing mechanism rationally. This article will introduce the Golang channel closing mechanism and how to avoid some common mistakes.

1. Introduction to Golang channel

Golang's channel is a data structure used for communication between multiple goroutines. It provides two main operations: send and receive. By calling operations, data can be safely transferred between goroutines. The following is the syntax for creating a channel:

ch := make(chan type)

where type can be any basic type or custom type. Values ​​can be sent to the channel through the following syntax:

ch <- value

Similarly, values ​​can be received from the channel through the following syntax:

value := <- ch

When there is no value to receive, the receiving operation will be blocked; The send operation will block when there is no room to send the value. This mechanism ensures synchronization between goroutines and correct transmission of data.

2. Close Golang channel

In Go programming, the operation of closing the channel is very important. When the sending direction sends data to a closed channel, it will cause panic; when the receiving direction receives data from a closed channel, if there is no data in the channel, the receiving operation will return an explicit zero value. If there is still data in the channel, then The receive operation will return the unprocessed data in the channel.

The syntax for closing a channel is as follows:

close(ch)

When the channel is closed, all sending operations will cause panic, but receiving operations can continue to read the remaining sent values. When multiple goroutines operate the same channel concurrently, the shutdown mechanism can well control the communication and synchronization between these goroutines.

3. Avoid common errors in channel closing

When using the channel closing mechanism, you need to pay attention to some common errors, otherwise it may cause program errors or affect performance. Here are some common questions.

1. Close the channel multiple times

Calling the close operation multiple times on the same channel will cause panic. Therefore, when closing a channel, you need to ensure that the close operation is only called once.

2. Sending data to a closed channel

When sending data to a closed channel, panic will occur. Therefore, before sending data, you need to ensure that the channel is not closed.

3. Reading data from a closed channel

Reading data from a closed channel will not cause panic, but will return if there is no unprocessed data An unambiguous zero value. Before reading channel data, you need to ensure that the channel has not been closed.

4. Summary

This article introduces the closing mechanism of Golang channel and matters that need to be paid attention to in practice. In concurrent programming, rational use of the channel closing mechanism can not only improve the robustness and performance of the program, but also ensure safe communication between multiple goroutines. Therefore, in Golang programming, it is very important to understand and master the channel closing mechanism.

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