以下涉及 Go 中通道的函数参数有什么区别？

Question

此代码在函数参数中使用 通道运算符：

func Worker(item <- chan string)

并且此代码在函数参数中没有通道运算符：

func Worker(item chan string)

Answer 1

The optional <- operator specifies the channel direction, send or receive. If no direction is given, the channel is bidirectional. A channel may be constrained only to send or only to receive by conversion or assignment.

来自 golang 规范：https://golang.org/ref/spec#Channel_types

Answer 2

func Worker(item <- chan string)

这里item是发送通道。您只能向它发送值而不能从中接收。

func Worker(item chan string)

这里item是一个双向通道。发送和接收都可以。

Answer 3

您可以尝试使用此代码示例来模拟通道方向。

// func Worker(item <- chan string) # Send or Receive
// func Worker(item chan string)    # Bidirectional

func sendOrRecvFunc(item <-chan string, msg *string) {
    *msg = <- item // send
}

func bidirectionalFunc(item chan string, msg string) {
    item <- msg // receive
}

func main() {

    // e.g Send or Receive
    var msg1 string

    item1 := make(chan string,1)

    item1 <- "message1" // receive

    sendOrRecvFunc(item1,&msg1)

    fmt.Println(msg1)

    //---------------------------------------------

    // e.g Bidirectional
    item2 := make(chan string,1)

    bidirectionalFunc(item2,"message2")

    msg2 := <- item2 // send

    fmt.Println(msg2)

}

// Output:
message1
message2

以下涉及 Go 中通道的函数参数有什么区别？

What's the difference between the following function arguments involving channels in Go?

arguments

function

channel

go