go sync.map example

syncmaprace.go

package main

import (
	"fmt"
	"sync"
	"time"
)

var arrTest = []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}

var minicache sync.Map

func towrite(text string) {
	for _, v := range arrTest {
		minicache.Store(v, text)
		time.Sleep(10 * time.Millisecond)
	}
}

func main() {

	go towrite("test1")

	go towrite("test2")

	go func() {

		time.Sleep(10 * time.Millisecond)
		for _, v := range arrTest {
			if val, ok := minicache.Load(v); ok {
				fmt.Println(v, val)
			} else {
				fmt.Println(v, "not get")
			}
			time.Sleep(10 * time.Millisecond)
		}

	}()

	time.Sleep(10 * time.Second)
}

If you use just a global map without syncmap and decrease timeout, the compiler will generate the error "fatal error: concurrent map writes"