epoll默认情况下是水平触发模式，这次将epoll设置为边缘触发模式来实现服务器，而客户端直接使用完美回声服务器的客户端。

服务器代码

#include

#include

#include

#include

#include

#include

#include

#include

#include

const int BUF_SIZE = 4;

const int EPOLL_SIZE = 50;

void setnonblockingmode(int fd);

void error_handling(const char *buf);

int main(int argc, char *argv[]) {

int server_sock, client_sock;

sockaddr_in server_addr, client_addr;

socklen_t addr_size;

ssize_t str_len;

int i;

char buf[BUF_SIZE];

epoll_event *ep_events;

epoll_event event;

int epfd, event_cnt;

if (argc != 2) {

printf("Usage : %s \n", argv[0]);

exit(1);

}

server_sock = socket(PF_INET, SOCK_STREAM, 0);

memset(&server_addr, 0, sizeof(server_addr));

server_addr.sin_family = AF_INET;

server_addr.sin_addr.s_addr = htonl(INADDR_ANY);

server_addr.sin_port = htons(atoi(argv[1]));

if (bind(server_sock, (sockaddr*)&server_addr, sizeof(server_addr)) == -1) {

error_handling("bind() error");

exit(1);

}

if (listen(server_sock, 5) == -1) {

error_handling("listen() error");

}

epfd = epoll_create(EPOLL_SIZE);

ep_events = (epoll_event*)malloc(sizeof(epoll_event) * EPOLL_SIZE);

event.events = EPOLLIN;

event.data.fd = server_sock;

epoll_ctl(epfd, EPOLL_CTL_ADD, server_sock, &event);

while (1) {

event_cnt = epoll_wait(epfd, ep_events, EPOLL_SIZE, -1);

if (event_cnt == -1) {

puts("epoll_wait() error");

break;

}

for (int i = 0; i < event_cnt; ++i) {

if (ep_events[i].data.fd == server_sock) {

addr_size = sizeof(client_addr);

client_sock = accept(server_sock, (sockaddr*)&client_addr, &addr_size);

setnonblockingmode(client_sock); // 设置client socket为非阻塞模式

event.events = EPOLLIN | EPOLLET; // 设置epoll边缘触发

event.data.fd = client_sock;

epoll_ctl(epfd, EPOLL_CTL_ADD, client_sock, &event);

printf("connect client: %d\n", client_sock);

} else {

while (1) { // 将数据读完为止

str_len = read(ep_events[i].data.fd, buf, BUF_SIZE);

if (str_len == 0) {

epoll_ctl(epfd, EPOLL_CTL_DEL, ep_events[i].data.fd, NULL);

close(ep_events[i].data.fd);

printf("closed client: %d\n", ep_events[i].data.fd);

} else if (str_len < 0) {

if (errno == EAGAIN) { // 已无数据

break;

}

}

else {

write(ep_events[i].data.fd, buf,str_len);

}

}

}

}

}

close(server_sock);

close(epfd);

return 0;

}

// 将文件描述符设置为非阻塞

void setnonblockingmode(int fd) {

int flag = fcntl(fd, F_GETFL, 0);

fcntl(fd, F_SETFL, flag | O_NONBLOCK);

}

项目代码

参考