epoll实例

#include <iostream>
#include <sys/socket.h>
#include <sys/epoll.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>

using namespace std;

#define MAXLINE 5
#define OPEN_MAX 100
#define LISTENQ 20
#define SERV_PORT 5000
#define INFTIM 1000

void setnonblocking(int sock)
{
    int opts;
    opts=fcntl(sock,F_GETFL);
    if(opts<0)
    {
        perror("fcntl(sock,GETFL)");
        exit(1);
    }
    opts = opts|O_NONBLOCK;
    if(fcntl(sock,F_SETFL,opts)<0)
    {
        perror("fcntl(sock,SETFL,opts)");
        exit(1);
    }
}

int main(int argc, char* argv[])
{
    int i, maxi, listenfd, connfd, sockfd,epfd,nfds, portnumber;
    ssize_t n;
    char line[MAXLINE];
    socklen_t clilen;


    if ( 2 == argc ){
        if( (portnumber = atoi(argv[1])) < 0 ){
            fprintf(stderr,"Usage:%s portnumber\n",argv[0]);
            return 1;
        }
    }
    else{
        fprintf(stderr,"Usage:%s portnumber\n",argv[0]);
        return 1;
    }
    
    struct epoll_event ev,events[20];
   
    epfd=epoll_create(256);
    struct sockaddr_in clientaddr;
    struct sockaddr_in serveraddr;
    
    listenfd = socket(AF_INET, SOCK_STREAM, 0);
    
    setnonblocking(listenfd);

    ev.data.fd=listenfd;
    ev.events=EPOLLIN|EPOLLET;
    
    //ev.events=EPOLLIN;

    epoll_ctl(epfd,EPOLL_CTL_ADD,listenfd,&ev);
    bzero(&serveraddr, sizeof(serveraddr));
    serveraddr.sin_family = AF_INET;
    char *local_addr="127.0.0.1";
    
    inet_aton(local_addr,&(serveraddr.sin_addr));
    serveraddr.sin_port=htons(portnumber);
    
    bind(listenfd,(sockaddr *)&serveraddr, sizeof(serveraddr));
    listen(listenfd, LISTENQ);
    
    maxi = 0;
    for ( ; ; ) 
    {
        nfds=epoll_wait(epfd,events,20,500);
        for(i=0;i<nfds;++i)
        {
            if(events[i].data.fd==listenfd)

            {
                connfd = accept(listenfd,(sockaddr *)&clientaddr, &clilen);
                if(connfd<0){
                    perror("connfd<0");
                    exit(1);
                }
                setnonblocking(connfd);

                char *str = inet_ntoa(clientaddr.sin_addr);
                cout << "Accept a connection from " << str << endl;
               

                ev.data.fd=connfd;
                ev.events=EPOLLIN|EPOLLET;
                //ev.events=EPOLLIN;
                epoll_ctl(epfd,EPOLL_CTL_ADD,connfd,&ev);
            }
            else if(events[i].events&EPOLLIN)

            {
                cout << "EPOLLIN" << endl;
                if ( (sockfd = events[i].data.fd) < 0)
                    continue;
                if ( (n = read(sockfd, line, MAXLINE)) < 0) {
                    if (errno == ECONNRESET) {
                        close(sockfd);
                        events[i].data.fd = -1;
                    } 
		    else
                        std::cout<<"readline error"<<std::endl;
                } 
		else if (n == 0) {
                    close(sockfd);
                    events[i].data.fd = -1;
                }
                line[n] = '/0';
            
                ev.data.fd=sockfd;
                ev.events=EPOLLOUT|EPOLLET;
                epoll_ctl(epfd,EPOLL_CTL_MOD,sockfd,&ev);
            }
            else if(events[i].events&EPOLLOUT) 
            {
            	cout << "EPOLLOUT" << endl;
                sockfd = events[i].data.fd;
                write(sockfd, line, n);
              
                ev.data.fd=sockfd;
                ev.events=EPOLLIN|EPOLLET;
                epoll_ctl(epfd,EPOLL_CTL_MOD,sockfd,&ev);
            }
        }
    }

    return 0;
}

#include<stdlib.h>
#include<iostream>
#include<sys/socket.h>
#include<sys/epoll.h>
#include<arpa/inet.h>
#include<netinet/in.h>
#include<unistd.h>
#include<errno.h>
#include<string.h>
#include<stdio.h>
#include<fcntl.h>

using namespace std;

#define MAXLINE 1024
#define LISTEN 25
#define PORT 5000


void setnonblocking(int fd)
{
	int ret;
	ret=fcntl(fd,F_GETFL);
	if(ret<0){
		perror("fcntl error");
		exit(-1);
	}

	ret=ret|O_NONBLOCK;

	if(fcntl(fd,F_SETFL,ret)<0){
		perror("fcntl error");
		exit(-1);
	}
}

int main()
{
	int sock,conn,epfd,nfds,max;
	struct sockaddr_in serveraddr,clientaddr;
	int n,yes=1,i,fd;
	char line[MAXLINE];
	socklen_t len;
	char *localaddr="127.0.0.1";

	struct epoll_event ev,events[20]; //important define

	epfd = epoll_create(256);

	//memset(serveraddr,0,sizeof(struct sockaddr_in));
	//memset(clientaddr,0,sizeof(struct sockaddr_in));

	sock = socket(AF_INET,SOCK_STREAM,0);
	if(sock<0){
		perror("socket error");
		exit(-1);
	}

	if(setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,&yes,(socklen_t)(sizeof(yes)))<0){
		perror("setsockopt eror");
		exit(-1);
	}

	setnonblocking(sock);

	ev.data.fd = sock;
	ev.events = EPOLLIN|EPOLLET;  

	epoll_ctl(epfd,EPOLL_CTL_ADD,sock,&ev);

	serveraddr.sin_family = AF_INET;
	serveraddr.sin_port = htons(PORT);
	inet_aton(localaddr,&(serveraddr.sin_addr));


	if(bind(sock,(struct sockaddr*)&serveraddr,sizeof(serveraddr))<0){
		perror("bind error");
		exit(-1);
	}

	if(listen(sock,LISTEN)<0){
		perror("listen error");
		exit(-1);
	}


	int rc=0;
	int wc=0;

	while(1)
	{
		nfds = epoll_wait(epfd,events,20,500);
		if(nfds<0){
			if(errno==EINTR){
				continue;
			}
		}
		
		
		for(i=0;i<nfds;i++)
		{
			if(events[i].data.fd == sock){
				cout<<"+++++++++++++++accept+++++++++++++"<<endl;
				len = sizeof(clientaddr);
				conn = accept(sock,(struct sockaddr*)&clientaddr,&len);
				if(conn<0){
					perror("accept error");
					exit(-1);
				}

				setnonblocking(conn);

				ev.data.fd = conn;
				ev.events = EPOLLIN|EPOLLET;
				epoll_ctl(epfd,EPOLL_CTL_ADD,conn,&ev);
			}
			else if(events[i].events&EPOLLIN){
			//	cout<<"+++++++++++++++EPOLLIN++++++++++++++++"<<endl;
				
				fd=events[i].data.fd;
				memset(line,0,MAXLINE);
				n=read(fd,line,MAXLINE);
			
				if(n<0){
					ev.data.fd = events[i].data.fd;
					ev.events = EPOLLIN|EPOLLET;
					epoll_ctl(epfd,EPOLL_CTL_MOD,fd,&ev);
					continue;

				}
				else if(n==0){
					ev.data.fd = events[i].data.fd;
					close(fd);
					epoll_ctl(epfd, EPOLL_CTL_DEL, fd, &ev);
					continue;		
				}
				
				if(n>0){
					line[++n]='\0';
					cout<<"Read:"<<line<<endl;
					rc++;
				}
				
				ev.data.fd=fd;
				ev.events = EPOLLOUT|EPOLLET;
				epoll_ctl(epfd,EPOLL_CTL_MOD,fd,&ev);
			}
			else if(events[i].events&EPOLLOUT){
			//	cout<<"+++++++++++EPOLLOUT+++++++++++++"<<endl;
				
				int ret;
				int fd1=events[i].data.fd;
				ret=write(fd1,line,n+1);
				
				if(ret<0){
					ev.data.fd=events[i].data.fd;
					ev.events = EPOLLOUT|EPOLLET;
					epoll_ctl(epfd,EPOLL_CTL_MOD,fd1,&ev);
					continue;
				}
				else if(ret==0){
					ev.data.fd = events[i].data.fd;
					close(fd1);
					epoll_ctl(epfd, EPOLL_CTL_DEL, fd1, &ev);
					continue;
				}
				
				if(ret>0){
					cout<<"Write to client:"<<line<<endl;
					memset(line,0,MAXLINE);
				}
				
				ev.data.fd = fd1;
				ev.events = EPOLLIN|EPOLLET;
				epoll_ctl(epfd,EPOLL_CTL_MOD,fd1,&ev);
			}
		}
	}

	return 0;
}

http://blog.youkuaiyun.com/ljx0305/article/details/4065058

http://www.cppblog.com/converse/archive/2008/10/12/63836.html