ok pattern 測試，
func main() {
c := make(chan []int)
a := []int{1, 2, 3, 4}
go func() {
c <- a
close(c)
}()
for i := 1; i <= 3; i++ {
t, ok := <-c
fmt.Println(i, ":", t, ok)
}
}
/*輸出：
1 : [1 2 3 4] true
2 : [] false
3 : [] false
*/
func main() {
c := make(chan []int, 1)
a := []int{1, 2, 3, 4}
go func() {
c <- a
close(c)
}()
for i := 1; i <= 3; i++ {
t, ok := <-c
fmt.Println(i, ":", t, ok)
}
}
/*輸出：
1 : [1 2 3 4] true
2 : [] false
3 : [] false
*/
func main() {
c := make(chan []int, 1)
a := []int{1, 2, 3, 4}
go func() {
c <- a
}()
time.Sleep(2 * time.Second)
close(c)
for i := 1; i <= 3; i++ {
t, ok := <-c
fmt.Println(i, ":", t, ok)
}
}
/*輸出：
1 : [1 2 3 4] true
2 : [] false
3 : [] false
*/
func main() {
c := make(chan []int)
a := []int{1, 2, 3, 4}
go func() {
c <- a
}()
time.Sleep(2 * time.Second)
close(c)
for i := 1; i <= 3; i++ {
t, ok := <-c
fmt.Println(i, ":", t, ok)
}
}
/*輸出：
panic: send on closed channel
goroutine 18 [running]:
main.main.func1(0xc00009c000, 0xc00009e000, 0x4, 0x4)
/Users/xxx/temp/gotest/gotest.go:30 +0x53
created by main.main
/Users/xxx/temp/gotest/gotest.go:29 +0xb5
exit status 2
*/
結論：
1.不要在channel的接收端關閉channel，如果channel不帶緩存，即使先執行發送數據的動作，也會導致panic。
2. 在channel的發送端關閉channel，關閉後channel中的數據可以用OK pattern讀取到