多线程控制台输出？

Question

If I have multiple go-routines going and 2 or more of them decide they need to print something out, is it possible for them to interrupt each other?

For example:

package main

import (
    "fmt"
)

func main() {
    go print()
    print()
}

func print() {
    for true {
        fmt.Print("ABCDEF")
    }
}

Is it possible for one go-routine to start printing (AB) and another go-routine interrupting (ABABCDEF) and the original finishing (ABABCDEFCDEF)?

I've tried running it myself and checking the output and it looks good, but how can I be sure?

Answer 1

Yes, it's possible, though you won't see any with GOMAXPROCS=1. They will show up when running with more goroutines, larger lines, and more threads. Even more so when writing to stderr, which is unbuffered, since the stdout buffer accepts the short writes fast enough to help prevent interleaving.

This is why the Logger in the "log" package has an internal mutex and buffer, to properly serialize the calls.