package main
import (
"fmt"
"sync"
"time"
)
/*传统的同步机制很少使用到，因为传统的同步机制都是用共享内存来交换数据的，所以才需要mutxt cond去保护*/
type atomicInt struct {
value int
lock sync.Mutex //锁
}
/*atomic 在多个goroutine之间是安全的*/
//互斥量
func (a *atomicInt) increment(){
a.lock.Lock() //锁住数据
defer a.lock.Unlock()//做完之后解锁数据
a.value ++
}
//将锁控制在一段代码区域中
func (a *atomicInt) incremenSafeSpace(){
fmt.Println("safe space:start")
func(){
a.lock.Lock() //锁住数据
defer a.lock.Unlock()//做完之后解锁数据
a.value ++
}()
fmt.Println("safe space:end")
}
func (a *atomicInt) get() int {
a.lock.Lock()
defer a.lock.Unlock()
return a.value
}
func main() {
var a atomicInt
a.increment()
go func() {
//写
a.incremenSafeSpace()
}()
time.Sleep(time.Second)
//读
//
fmt.Println(a.get())
/* 在读的时候写，发生了冲突
go run -race atomic.go
==================
WARNING: DATA RACE
Read at 0x00c000096008 by main goroutine:
main.main()
/Users/tao/go/src/learn/basic/channel10/atomic/atomic.go:31 +0xc5
Previous write at 0x00c000096008 by goroutine 7:
main.main.func1()
/Users/tao/go/src/learn/basic/channel10/atomic/atomic.go:14 +0x51
Goroutine 7 (finished) created at:
main.main()
/Users/tao/go/src/learn/basic/channel10/atomic/atomic.go:24 +0xaa
==================
*/
}
