func testRead() { ch := make(chan int, 10) ch <- 1 close(ch) num, ok := <-ch if ok { fmt.Println("read: ", num) } num, ok = <-ch if !ok { fmt.Println("read from closed channel: ", num) } } 输出: read: 1 read from
已关闭的channel再次读取会出现什么现象? 如何判断channel关闭? 什么是nil channel有什么用? 先看看出问题的代码片段: func TestReadFromClosedChan(t *testing.T) { asChan := func(vs ...int) <-chan int { c := make(chan int) go func() { for _, v := range vs { c <- v time.Sleep(tim...
$ go run readCh.go 1 10 Read: 10 2 10 Channel is closed! $ go run readCh.go 1 10 2 ...
lock) panic(plainError("send on closed channel")) } } 写一个closed的channel会导致panic 验证 RunNilChan封装了读写一个nil的例子,从运行角度发现读写过程都是会导致goroutine阻塞 RunClosedChan封装了读写一个closed的channel的例子,从运行角度发现读已经closed的channel会阻塞;写已经closed的channel会触发...
elemtype channel中的元素类型 closed 通道关闭标志 recvq 因读取channel而陷入阻塞的协程等待队列 sendq 因发送channel而陷入阻塞的协程等待队列 lock 锁 waitq // 等待队列(双向链表)typewaitqstruct{ first *sudog last *sudog } waitq是因读写channel而陷入阻塞的协程等待队列。
if c.closed != 0 { goto rclose } case caseSend: // ch <- 1 的情况,也是一些基本的 channel 操作 if raceenabled { racereadpc(unsafe.Pointer(c), cas.pc, chansendpc) } if c.closed != 0 { goto sclose } sg = c.recvq.dequeue() ...
src/runtime/chan.go:hchan定义了channel的数据结构:type hchan struct { qcount uint // 当前队列中剩余元素个数 dataqsiz uint // 环形队列长度,即可以存放的元素个数 buf unsafe.Pointer // 环形队列指针 elemsize uint16 // 每个元素的大小 closed uint32 // 标识关闭状态 elemtype *_type // 元素...
fmt.Printf("Value %d was read.\n", x) } else { fmt.Println("Channel closed!") //Channel 被close. } default: fmt.Println("No value ready, moving on.") //Channel 沒有設定過,會馬上離開... } } Referhere. 進階的用法 這裏附上另外一個select的用法,就是來取得多個channel的資料.並且...
// the return value from Close. type bodyEOFSignal struct { body io.ReadCloser mu sync.Mutex // guards following 4 fields closed bool // whether Close has been called rerr error // sticky Read error fn func(error) error // err will be nil on Read io.EOF ...
}// ReadWriter interface use for handle application packagestypeReadWriterinterface{ Reader Writer } // EventListener is used to process pkg that received from remote sessiontypeEventListenerinterface{// invoked when session opened// If the return error is not nil, @Session will be closed.OnOpen...