48 lines
1.1 KiB
Go
48 lines
1.1 KiB
Go
// To wait for multiple goroutines to finish, we can
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// use a *wait group*.
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package main
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import (
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"fmt"
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"sync"
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"time"
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)
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// This is the function we'll run in every goroutine.
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// Note that a WaitGroup must be passed to functions by
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// pointer.
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func worker(id int, wg *sync.WaitGroup) {
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// On return, notify the WaitGroup that we're done.
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defer wg.Done()
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fmt.Printf("Worker %d starting\n", id)
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// Sleep to simulate an expensive task.
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time.Sleep(time.Second)
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fmt.Printf("Worker %d done\n", id)
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}
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func main() {
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// This WaitGroup is used to wait for all the
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// goroutines launched here to finish.
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var wg sync.WaitGroup
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// Launch several goroutines and increment the WaitGroup
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// counter for each.
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for i := 1; i <= 5; i++ {
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wg.Add(1)
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go worker(i, &wg)
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}
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// Block until the WaitGroup counter goes back to 0;
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// all the workers notified they're done.
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wg.Wait()
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// Note that this approach has no straightforward way
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// to propagate errors from workers. For more
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// advanced use cases, consider using the
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// [errgroup package](https://pkg.go.dev/golang.org/x/sync/errgroup).
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}
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