golang sync.Mutex

//go func 和主线程之间的关系是并行和竞争关系


package main



import (

    "fmt"

    "sync"

    "time"

)



var l sync.Mutex

var m *sync.Mutex



func main() {



    m = new(sync.Mutex)



    go lock(1)

    time.Sleep(3 * time.Second)



    fmt.Printf("%s\n", "exit!")



}

func lock(i int) {

    println(i, "lock start")



    m.Lock()

    println(i, "lock")



    time.Sleep(3 * time.Second)



    m.Unlock()

    println(i, "unlock")

}