WaitGroup.Go in Go

Go 1.25 added Go, which does the Add and Done for you.

func square(values []int) []int {
    results := make([]int, len(values))
    var wg sync.WaitGroup

    for i, value := range values {
        wg.Go(func() {
            results[i] = value * value // each index is written once
        })
    }

    wg.Wait()
    return results
}

How it works

1. wg.Go(f) replaces Add, a goroutine and a deferred Done.
2. Wait still blocks until every task has finished.
3. Results still need a channel or a mutex; the group only counts.

Keywords and builtins used here

• for
• func
• int
• len
• make
• range
• return
• var

The run, in numbers

Lines

13

Characters to type

228

Tokens

66

Three-star pace

95 tpm

At the three-star pace of 95 tokens a minute, this run takes about 42 seconds.

Type this snippet

Step 2 of 3 in Goroutines, step 2 of 25 in Concurrency.

← Previous Next →