對int類型進行i++自增操作時並不是原子操作，併發不安全

 

package main

import (
	"fmt"
	"runtime"
	"sync"
)

func main() {
	runtime.GOMAXPROCS(5)
	var m int32 = 0

	var group sync.WaitGroup

	for i := 0; i < 100000; i++ {
		group.Add(1)
		go func() {
			defer func() { group.Done() }()
			// atomic.AddInt32(&m, 1)
			m++
			// fmt.Println(m)
		}()
	}

	group.Wait()
	fmt.Print(m)
}