服务器端
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/epoll.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define BUFESIZE 5
#define OPEN_MAX 100
#define LISTENQ 20
#define SERV_PORT 5000
#define INFTIM 1000
// 把socket设置为非阻塞方式
void setNonBlocking(int sock)
{
int opts = fcntl(sock, F_GETFL);
if(opts < 0)
{
perror("fcntl(sock, F_GETFL");
exit(1);
}
opts |= O_NONBLOCK;
if(fcntl(sock, F_SETFL, opts) < 0)
{
perror("fcntl(sock, SETFL, opts");
exit(1);
}
}
int main(int argc, char *argv[])
{
int port;
if(argc == 2)
{
if((port = atoi(argv[1])) < 0)
{
fprintf(stderr, "Usage:%s port\n", argv[0]);
return 1;
}
}
else
{
fprintf(stderr, "Usage%s port\n", argv[0]);
return 1;
}
int listenfd = socket(AF_INET, SOCK_STREAM, 0);
setNonBlocking(listenfd);
// 创建epoll句柄
// int epoll_create(int size);
// size: epll支持的最大句柄数
int epfd = epoll_create(256);
// epoll要监听的事件
struct epoll_event ev;
ev.data.fd = listenfd; // 文件描述符
ev.events = EPOLLIN | EPOLLET; // 读 | 边缘触发
// 事件注册
// int epoll_ctl(int epfd, int op, int fd, struct epoll_event *event);
epoll_ctl(epfd, EPOLL_CTL_ADD, listenfd, &ev);
struct sockaddr_in serveraddr;
bzero(&serveraddr, sizeof(serveraddr);
serveraddr.sin_family = AF_INET; // 地址族
char *local_addr = "127.0.0.1";
inet_aton(local_addr, &(serveraddr.sin_addr)); // 地址
serveraddr.sin_port = htons(port); // 端口
bind(listenfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr));
listen(listenfd, LISTENQ);
struct sockaddr_in clientaddr;
socklen_t clilen;
char buf[BUFESIZE];
struct epoll_event events[20]; // epoll_wait成功之后,储存所有的读写事件
int n;
while(1)
{
// 等待直到注册的事件发生
// int epoll_wait(int epfd, struct epoll_event * events, int maxevents, int timeout);
// 返回需要处理的事件数目,如返回0表示已超时
int nfds = epoll_wait(epfd, events, 20, 500);
for(int i=0; i<nfds; ++i)
{
if(events[i].data.fd == listenfd) // 有新的连接
{
int clientfd = accept(listenfd, (struct sockaddr *)&clientaddr, &clilen);
if(clientfd < 0)
{
perror("clientfd < 0");
exit(1);
}
setNonBlocking(clientfd);
char *str = inet_ntoa(clientaddr.sin_addr);
printf("accept a connection from %s\n", str);
ev.data.fd = clientfd;
ev.events = EPOLLIN | EPOLLET;
// 将新的fd添加到epoll的监听队列中
epoll_ctl(epfd, EPOLL_CTL_ADD, clientfd, &ev);
}
else if(events[i].events & EPOLLIN) // 接收到数据,读socket
{
printf("EPOLLIN\n");
int sockfd;
if((sockfd = events[i].data.fd) < 0)
continue;
if((n = read(sockfd, buf, BUFESIZE)) < 0)
{
if(errno == ECONNRESET)
{
close(sockfd);
events[i].data.fd = -1;
}
else
printf("read error");
}
else if(n == 0)
{
close(sockfd);
events[i].data.fd = -1;
}
buf[n] = '\0';
printf("read %s\n", buf);
ev.data.fd = sockfd;
ev.events = EPOLLOUT | EPOLLET;
// 修改标识符,等待下一个循环时发送数据
epoll_ctl(epfd, EPOLL_CTL_MOD, sockfd, &ev);
}
else if(events[i].events & EPOLLOUT) // 有数据待发送,写socket
{
printf("EPOLLOUT\n");
int sockfd = events[i].data.fd;
write(sockfd, buf, n);
ev.data.fd = sockfd;
ev.events = EPOLLIN | EPOLLET;
// 修改标识符,等待下一个循环时接收数据
epoll_ctl(epfd, EPOLL_CTL_MOD, sockfd, &ev);
}
}
}
return 0;
}
客户端
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main()
{
int sockid = socket(AF_INET, SOCK_STREAM, 0);
if(sockid == -1)
perror("socket");
struct sockaddr_in saddr;
saddr.sin_family = AF_INET;
saddr.sin_addr.s_addr = inet_addr("127.0.0.1");
saddr.sin_port = htons(5000);
if(connect(sockid, (struct sockaddr*)&saddr, sizeof(saddr)) == -1)
perror("connect");
char buf[100] = "Hello!";
write(sockid, buf, sizeof(buf));
read(sockid, buf, sizeof(buf));
printf("%s\n", buf);
close(sockid);
return 0;
}
参考
https://blog.csdn.net/ljx0305/article/details/4065058
http://blog.jobbole.com/93566/