resultworkererr := make(chan error) defer close(resultworkererr) go func() {
时间: 2023-05-08 13:57:50 浏览: 134
这段代码是Go语言中使用goroutine实现并发编程的经典语句。其中,resultworkererr是一个通道(channel),用于在goroutine中传递错误信息;make(chan error)表示创建一个容量为1,元素类型为error的通道;defer close(resultworkererr)则表示在函数结束时关闭通道,避免泄漏。最后,通过go func()开启一个新的goroutine,在其中处理具体的操作,并将错误信息传递到通道中。这样就可以实现并发地执行任务,同时保证传递错误信息的可靠性。总之,Go语言中的goroutine和通道是其并发模型的两个重要组成部分,可以极大地提高程序的并发执行效率和可维护性。
相关问题
func (sc *psrtpConn) run() { defer sc.s.wg.Done() readErr := make(chan error) go sc.runReader(readErr) select { case err := <-readErr: sc.log(logger.Error, "readErr:%v", err) sc.s.connClose <- sc sc.close() return case <-sc.ctx.Done(): sc.log(logger.Error, "ctx canceled") sc.close() return } }中runReader会在什么时候调用
在这段代码中,`runReader` 是在 `run` 函数中作为 goroutine 调用的。具体来说,`go sc.runReader(readErr)` 会启动一个 goroutine 来执行 `runReader` 函数,并将一个用于通知错误的 channel `readErr` 传递给 `runReader` 函数。在 `runReader` 函数内部,如果发生了错误,会通过 `readErr` channel 发送错误信息。而在 `run` 函数中,通过 `select` 语句来监听 `readErr` channel 和 `sc.ctx.Done()` channel,一旦有一个 channel 有了结果,就会执行相应的代码,要么关闭连接,要么返回。因此,`runReader` 函数会在 `run` 函数的开头被调用。
go lang defer close
In Go language, the `defer` statement is used to schedule a function call to be executed at the end of the current function, but before it returns. This is often used to ensure that resources are released or other cleanup tasks are performed regardless of whether an error is encountered or not.
For example, let's say you have opened a file in a function and you want to make sure that the file is closed before the function returns, you can use `defer` statement to close the file:
```
func readFromFile(filename string) error {
f, err := os.Open(filename)
if err != nil {
return err
}
defer f.Close() // ensure file is closed before function returns
// read from file
// ...
return nil
}
```
In this example, the `f.Close()` function call is scheduled to be executed at the end of the `readFromFile` function, but before it returns, regardless of whether an error is encountered or not.
Now, let's talk about `close` statement. In Go, channels can be closed using the `close` function. A closed channel indicates that no more values will be sent to it. Receiving from a closed channel will return the zero value for the channel's type.
Here's an example of closing a channel using the `close` function:
```
ch := make(chan int)
go func() {
for i := 0; i < 5; i++ {
ch <- i
}
close(ch)
}()
for v := range ch {
fmt.Println(v)
}
```
In this example, a new goroutine is launched to send values to the channel `ch`. After sending 5 values, the channel is closed using the `close` function. Then, in the main goroutine, values are received from the channel using a `for range` loop until the channel is closed.