驱动开发6 IO多路复用——epoll

核心操作：一棵树、一张表、三个接口

相关案例

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <sys/select.h>
#include <sys/epoll.h>
/* According to earlier standards */
#include <sys/time.h>int main(int argc, char const *argv[])
{int fd1, fd2, epfd;struct epoll_event event;      // 用于操作epollstruct epoll_event events[10]; // 存放就绪事件描述符的数组char buf[128] = {0};// 创建epoll句柄epfd = epoll_create(1);if (epfd < 0){printf("epoll_create filed\n");exit(-1);}// 打开设备文件fd1 = open("/dev/input/mouse0", O_RDWR);if (fd1 < 0){printf("打开鼠标设备文件失败\n");exit(-1);}fd2 = open("/dev/mycdev0", O_RDWR);if (fd2 < 0){printf("打开鼠标设备文件失败\n");exit(-1);}// 添加准备就绪事件进入epoll;event.events = EPOLLIN; // 读事件event.data.fd = fd1;if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd1, &event) < 0){printf("epoll_ctl add filed\n");}event.events = EPOLLIN; // 读事件event.data.fd = fd2;if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd2, &event) < 0){printf("epoll_ctl add filed\n");}// 监听事件是否发生while (1){// 如果成功，ret接收返回的事件个数，把就绪的事件放在events数组中int ret = epoll_wait(epfd, events, 10, -1);if (ret < 0){printf("epoll_wait filed\n");exit(-1);}int i;// 循环遍历数组，做事件的处理for (i = 0; i < ret; i++){if (events[i].events & EPOLLIN)//判断发生的事件是不是读事件{read(events[i].data.fd, buf, sizeof(buf));printf("buf:%s\n", buf);}}}close(fd1);close(fd2);return 0;
}

效果呈现