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51 lines
1.3 KiB
Go
51 lines
1.3 KiB
Go
// _Closing_ a channel indicates that no more values
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// will be sent on it. This can be useful to communicate
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// completion to the channel's receivers.
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package main
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import "fmt"
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// In this example we'll use a `jobs` channel to
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// communicate work to be done from the `main()` goroutine
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// to a worker goroutine. When we have no more jobs for
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// the worker we'll `close` the `jobs` channel.
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func main() {
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jobs := make(chan int, 5)
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done := make(chan bool)
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// Here's the worker goroutine. It repeatedly receives
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// from `jobs` with `j, more := <-jobs`. In this
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// special 2-value form of receive, the `more` value
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// will be `false` if `jobs` has been `close`d and all
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// values in the channel have already been received.
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// We use this to notify on `done` when we've worked
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// all our jobs.
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go func() {
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for {
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j, more := <-jobs
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if more {
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fmt.Println("received job", j)
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} else {
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fmt.Println("received all jobs")
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done <- true
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return
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}
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}
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}()
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// This sends 3 jobs to the worker over the `jobs`
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// channel, then closes it.
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for j := 1; j <= 3; j++ {
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jobs <- j
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fmt.Println("sent job", j)
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}
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close(jobs)
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fmt.Println("sent all jobs")
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// We await the worker using the
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// [synchronization](channel-synchronization) approach
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// we saw earlier.
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<-done
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}
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