Channels in Go

Typed pipes that carry values between goroutines.

func produce(n int) <-chan int {
    out := make(chan int)
    go func() {
        defer close(out)
        for i := 1; i <= n; i++ {
            out <- i * i
        }
    }()
    return out
}

func consume(in <-chan int) int {
    total := 0
    for v := range in {
        total += v
    }
    return total
}

How it works

1. A producer sends and then closes the channel.
2. <-chan int is a receive-only channel type.
3. range over a channel ends when it closes.

Keywords and builtins used here

• chan
• close
• defer
• for
• func
• go
• int
• make
• range
• return

The run, in numbers

Lines

18

Characters to type

235

Tokens

77

Three-star pace

100 tpm

At the three-star pace of 100 tokens a minute, this run takes about 46 seconds.

Type this snippet

Step 3 of 4 in Channels, step 6 of 25 in Concurrency.

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Channels in other languages

• Rust