go语言坑之并发访问map

fatal error: concurrent map read and map write

并发访问map是不安全的，会出现未定义行为，导致程序退出。所以如果希望在多协程中并发访问map，必须提供某种同步机制，一般情况下通过读写锁sync.RWMutex实现对map的并发访问控制，将map和sync.RWMutex封装一下，可以实现对map的安全并发访问，示例代码如下：

 

package main

import "sync"

type SafeMap struct {
    sync.RWMutex
    Map map[int]int } func main() { safeMap := newSafeMap(10) for i := 0; i < 100000; i++ { go safeMap.writeMap(i, i) go safeMap.readMap(i) } } func newSafeMap(size int) *SafeMap { sm := new(SafeMap) sm.Map = make(map[int]int) return sm } func (sm *SafeMap) readMap(key int) int { sm.RLock() value := sm.Map[key] sm.RUnlock() return value } func (sm *SafeMap) writeMap(key int, value int) { sm.Lock() sm.Map[key] = value sm.Unlock() }