go 通道的阻塞測試

go版本

go version go1.11.2 linux/amd64

無緩衝通道

測試樣例

package main

import "fmt"

func main(){
naturals:=make(chan int,0)//無緩存通道
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)
}


}

輸出

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

總結

重點是開頭的

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

無緩衝通道能夠塞進一個信息，而後繼續往下走，
若是這個信息尚未接收，繼續發送消息，則會形成阻塞，會切換到另一個goroutine

有緩衝通道

測試樣例

package main

import "fmt"

func main(){


naturals:=make(chan int,1)//有緩存通道 容量爲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)
}


}

輸出

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

總結

重點是開頭的

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

容量爲1的有緩衝通道能夠塞進2個信息，而後繼續往下走，
若是這2個信息尚未接收，繼續發送消息，則會形成阻塞，會切換到另一個goroutine