Golang实例讲解，数字递增的线程安全性问题

/**
 * 并发编程，数字递增的线程安全性问题
 */
package main

import (
   "sync"
   "time"
   "fmt"
   "sync/atomic"
)

var data1 int = 0
var data2 *int32
var wgInt sync.WaitGroup = sync.WaitGroup{}

func main() {
   t := int32(0)
   data2 = &t
   max := 100000
   wgInt.Add(max)
   fmt.Printf("data1 add num=%d\n", max)
   time1 := time.Now().UnixNano()
   for i := 0; i < max; i++ {
      go addData1()
   }
   wgInt.Wait()
   time2 := time.Now().UnixNano()
   fmt.Printf("data1=%d, time=%d ms\n", data1, (time2-time1)/1000000)

   wgInt.Add(max)
   fmt.Printf("data2 add num=%d\n", max)
   time3 := time.Now().UnixNano()
   for i := 0; i < max; i++ {
      go addData2()
   }
   wgInt.Wait()
   time4 := time.Now().UnixNano()
   fmt.Printf("data2=%d, time=%d ms\n", *data2, (time4-time3)/1000000)
}
// 简单的+1处理，线程不安全
func addData1() {
   data1++
   wgInt.Done()
}
// 原子性+1处理，线程安全
func addData2() {
   atomic.AddInt32(data2, 1)
   wgInt.Done()
}

data1 add num=100000

data1=98626, time=22 ms

data2 add num=100000

data2=100000, time=26 ms