sync_map_example.go

package main

import (
	"fmt"
	"sync"
)

var cache = sync.Map{}

func main() {

	var wg sync.WaitGroup
	wg.Add(2)

	go func() {
		for i := 0; i < 1000; i++ {
			if value, ok := cache.LoadOrStore("A", 1); ok {
				cache.Store("A", value.(int)+1)
			}
		}
		wg.Done()
	}()

	go func() {
		for i := 0; i < 1000; i++ {
			if value, ok := cache.LoadOrStore("B", 1); ok {
				cache.Store("B", value.(int)+1)
			}
		}
		wg.Done()
	}()

	wg.Wait()
	fmt.Println(cache.Load("A"))
	fmt.Println(cache.Load("B"))

}