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golang的chan特性

 3 years ago
source link: https://studygolang.com/articles/31838
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go routine之间可以通过channel来通信。

1、单向channel&双向channel

<-chan只能用来发送的单向channel；chan<-只能用来接收的单向channel；chan双向channel 向<-chan发送数据 或者 接收chan<-的数据；编译失败

var cc = make(<-chan int)
	close(cc)
	cc <- 23
# command-line-arguments
.\main.go:48:7: invalid operation: close(cc) (cannot close receive-only channel)
.\main.go:49:5: invalid operation: cc <- 23 (send to receive-only type <-chan int)
var cc = make(chan<- int)
	v:= <-cc
# command-line-arguments
.\main.go:49:6: invalid operation: <-cc (receive from send-only type chan<- int)

单向channel的应用场景是什么呢，回头研究一下。

2、channel的声明声明一个传输整形的buffer chan，容量为6： 

var cc = make(chan int, 6)

读缓存中为空的channel和写入缓存已满的channel都是阻塞的

因此，声明channel必须指定容量，channel才"可用"，否则channel的读写是阻塞的

3、channel使用完毕，使用close(c chan<- Type)关闭channel

向关闭的channel发送数据，会导致panic

***
	var cc = make(chan int,1)
	close(cc)
	cc <- 23
	***

panic: send on closed channel

report

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