resultworkererr := make(chan error) defer close(resultworkererr) go func() {

这是一段 Go 代码，其中创建了一个名为 `resultworkererr` 的无缓冲通道，并使用 `defer` 关键字在函数结束前关闭了该通道。接着使用匿名函数开启了一个 goroutine，其中会执行一些操作并可能会向 `resultworkererr` 通道发送错误信息。这段代码的作用可能是在并发操作中用于收集和汇总错误信息。

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.