go 通道的阻塞测试

go版本

go version go1.11.2 linux/amd64

无缓冲通道

测试样例

package main

import "fmt"

func main(){
naturals:=make(chan int,0)//无缓存通道
squares:=make(chan int)
go func(){
    for x:=0;x<10;x++{
        fmt.Println("naturals start ",x)
        naturals<-x
        fmt.Println("naturals end ",x)
    }
     fmt.Println("naturals close ")
    close(naturals)
}()

go func(){
    for x:=range naturals{
        fmt.Println("squares start ",x)
        squares<-x
        fmt.Println("squares end ",x)
    }
     fmt.Println("squares close ")
    close(squares)
}()

for x:=range squares{
    fmt.Println("main ",x)
}


}

输出

naturals start  0
naturals end  0
naturals start  1
squares start  0
squares end  0
squares start  1
naturals end  1
naturals start  2
main  0
main  1
squares end  1
squares start  2
squares end  2
main  2
naturals end  2
naturals start  3
naturals end  3
naturals start  4
squares start  3
squares end  3
squares start  4
naturals end  4
naturals start  5
main  3
main  4
squares end  4
squares start  5
squares end  5
main  5
naturals end  5
naturals start  6
naturals end  6
naturals start  7
squares start  6
squares end  6
squares start  7
naturals end  7
naturals start  8
main  6
main  7
squares end  7
squares start  8
squares end  8
main  8
naturals end  8
naturals start  9
naturals end  9
naturals close 
squares start  9
squares end  9
squares close 
main  9

总结

重点是开头的

naturals start  0
naturals end  0
naturals start  1
squares start  0

无缓冲通道可以塞进一个信息，然后继续往下走，
如果这个信息还没有接收，继续发送消息，则会造成阻塞，会切换到另外一个goroutine

有缓冲通道

测试样例

package main

import "fmt"

func main(){


naturals:=make(chan int,1)//有缓存通道 容量为1
squares:=make(chan int)
go func(){
    for x:=0;x<10;x++{
        fmt.Println("naturals start ",x)
        naturals<-x
        fmt.Println("naturals end ",x)
    }
     fmt.Println("naturals close ")
    close(naturals)
}()

go func(){
    for x:=range naturals{
        fmt.Println("squares start ",x)
        squares<-x
        fmt.Println("squares end ",x)
    }
     fmt.Println("squares close ")
    close(squares)
}()

for x:=range squares{
    fmt.Println("main ",x)
}


}

输出

naturals start  0
naturals end  0
naturals start  1
naturals end  1
naturals start  2
squares start  0
squares end  0
squares start  1
naturals end  2
naturals start  3
main  0
main  1
squares end  1
squares start  2
squares end  2
squares start  3
main  2
main  3
squares end  3
naturals end  3
naturals start  4
naturals end  4
naturals start  5
naturals end  5
naturals start  6
squares start  4
squares end  4
squares start  5
naturals end  6
naturals start  7
main  4
main  5
squares end  5
squares start  6
squares end  6
squares start  7
main  6
main  7
squares end  7
naturals end  7
naturals start  8
naturals end  8
naturals start  9
naturals end  9
naturals close 
squares start  8
squares end  8
squares start  9
main  8
main  9
squares end  9
squares close 

总结

重点是开头的

naturals start  0
naturals end  0
naturals start  1
naturals end  1
naturals start  2
squares start  0

容量为1的有缓冲通道可以塞进2个信息，然后继续往下走，
如果这2个信息还没有接收，继续发送消息，则会造成阻塞，会切换到另外一个goroutine