Buffered channels in Go

A buffer lets a sender run ahead, up to its capacity.

func buffered() (int, int, []int) {
    queue := make(chan int, 3)
    queue <- 1
    queue <- 2

    queued, capacity := len(queue), cap(queue)

    close(queue)
    var drained []int
    for value := range queue { // range stops at close
        drained = append(drained, value)
    }
    return queued, capacity, drained
}

How it works

1. make(chan T, n) holds n values before blocking.
2. len is what is queued, cap is the buffer size.
3. A full buffer blocks the sender; an empty one blocks the receiver.

Keywords and builtins used here

• append
• cap
• chan
• close
• for
• func
• int
• len
• make
• range
• return
• var

The run, in numbers

Lines

14

Characters to type

281

Tokens

74

Three-star pace

100 tpm

At the three-star pace of 100 tokens a minute, this run takes about 44 seconds.

Type this snippet

Step 2 of 4 in Channels, step 5 of 25 in Concurrency.

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