内核级事件回调demo
时间: 2024-09-07 07:04:36 浏览: 16
内核级事件回调在操作系统级别的网络编程中很常见,比如在Unix/Linux下的Epoll或者Windows下的IO Completion Ports(IOCP)。这里以Linux下Epoll为例,演示一个基本的客户端接受服务器数据的回调。
首先,你需要创建一个Epoll实例,然后将需要监控的文件描述符添加进去:
```c
#include <sys/epoll.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
int epoll_fd; // Epoll句柄
int client_socket; // 客户端的套接字描述符
void on_data_received(int fd) {
char buffer[1024];
ssize_t len = read(fd, buffer, sizeof(buffer));
if (len > 0) {
printf("Received data: %.*s\n", len, buffer);
// 对收到的数据做进一步处理...
} else if (len == 0) {
printf("Connection closed by server.\n");
} else {
perror("Reading error");
}
}
int main() {
epoll_fd = epoll_create1(0); // 创建epoll实例
if (epoll_fd < 0) {
perror("epoll_create1 failed");
return -1;
}
client_socket = connect_to_server(); // 建立与服务器的连接
if (client_socket < 0) {
perror("connect failed");
close(epoll_fd);
return -1;
}
struct epoll_event event;
event.events = EPOLLIN; // 监听读事件
event.data.fd = client_socket;
if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client_socket, &event) < 0) {
perror("epoll_ctl failed");
close(client_socket);
close(epoll_fd);
return -1;
}
// 开始主循环
while (true) {
struct epoll_event events[10];
int num_events = epoll_wait(epoll_fd, events, sizeof(events), -1);
for (int i = 0; i < num_events; i++) {
if (events[i].data.fd == client_socket && (events[i].events & EPOLLIN)) {
on_data_received(client_socket);
}
}
}
close(epoll_fd); // 关闭epoll句柄
return 0;
}
```
在这个例子中,`on_data_received`函数会在服务器数据到达客户端套接字时被调用。`epoll_wait`在主循环中持续监听事件,一旦数据可用,就会唤醒并执行相应的回调。