epoll监测不到/sys/class目录下的读写事件？

Posted 2022-07-30 上下求索.

EPOLL监测不到/sys/class目录下的读写事件？

//-------------------------------------------------------------------------------------
int GetWifiConnectionStatus()

    char buf[32] = 0;
    FILE *fp = fopen("/sys/class/net/wlan0/operstate", "r");
    if (!fp)       printf ("/sys/class/net/wlan0/operstate\\n");
        return 0;
    
    fread (buf, sizeof(char), sizeof(buf)-1, fp);               //printf ("buf:%s\\n", buf);
    fclose(fp);

    if (0 == strncmp("up", buf, 2))                            //printf ("opersatate:%s\\n", buf);
        return 1;
    

    return 0;


#define MAX_WIFI_EVENT 3
//-------------------------------------------------------------------------------------
void *ThrFunWaitWifiEvent(int bCW)

    int fd = open("/sys/class/net/wlan0/operstate", O_RDONLY);
    if (fd < 0)    printf ("open /sys/class/net/wlan0/operstate failed\\n");
        return -1;
    
	int epfd, nfds;
	struct epoll_event ev, events[MAX_WIFI_EVENT];      // ev用于注册事件，数组用于返回要处理的事件
	epfd = epoll_create(1);			                    //只需要监听一个描述符——标准输出
	ev.data.fd = fd;
	ev.events = EPOLLIN | EPOLLET;						//监听读状态同时设置ET模式
	epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev);            //注册epoll事件

	while (1)
		nfds = epoll_wait(epfd, events, MAX_WIFI_EVENT, -1);
		for (int i = 0; i < nfds; i++)
            if (events[i].events & EPOLLOUT)                printf ("operstatte EPOLLOUT\\n");
            if (events[i].events & EPOLLIN)                printf ("operstatte EPOLLIN\\n");
			if (events[i].data.fd == fd)
                if (GetWifiConnectionStatus())
                    printf("Network connected\\n");
                 else 
                    printf("Network disconnected\\n");
                
            
		
	

    if (fd>0)
        close(fd);
        fd = -1;