epoll

https://www.jianshu.com/p/718c24af400f

 

 

int r=0;
    r=set_noblock(socket_);
    if((r=connect(socket_, (struct sockaddr*)addr, sizeof(sockaddr_in_t))) <0){
        int err = errno;
        if(err == EISCONN)
            return 1;//"already con";
        else if(err != EINPROGRESS && err != EALREADY && err != EWOULDBLOCK && err)
            return -1;//"con error";
    }
    else{
        return 0;//"ok con";
    }
 
    fd_set readset, writeset, exceptionset;
    struct timeval tval;
    tval.tv_sec = 0;
    tval.tv_usec = 20000;
 
    //try now
    for(int i=1; i<=times; ++i){
        FD_ZERO(&readset);
        FD_SET(socket_, &readset);
 
        FD_ZERO(&writeset);
        FD_SET(socket_, &writeset);
 
        FD_ZERO(&exceptionset);
        FD_SET(socket_, &exceptionset);
 
        if((r=select(socket_+1, &readset, &writeset, &exceptionset, &tval)) < 0){
            if(errno == EINTR)
                continue;
            else
                return -2;//"select failed";
        }
        else if(r == 0){
            //"time out";
            continue;
        }
        else{
            if(FD_ISSET(socket_, &exceptionset)){
                if(i == times) return -4;//"exception";
                else continue;
            }
 
 
            if( FD_ISSET(socket_, &writeset)){
                if( FD_ISSET(socket_, &readset)){
                     if(i == times)   return -8; //error
                     else continue;
                }
                int error = 0;
                 socklen_t len = sizeof(error);
                int rc = getsockopt(socket_, SOL_SOCKET, SO_ERROR, (char *) &error, &len);
                if(rc == -1 || error)
                    if(i == times)  return -16;//"failed";
                    else continue;
                else{
                    return 0;
                    break;
                }
            }
 
        }
    }

 

 

 

server

#include <sys/epoll.h>
#include <fcntl.h>
#include <netinet/in.h>    // for sockaddr_in
#include <sys/types.h>    // for socket
#include <sys/socket.h>    // for socket
#include <stdio.h>        // for printf
#include <stdlib.h>        // for exit
#include <string.h>        // for bzero
#include <arpa/inet.h>     // inet_ntoa

#define LISTENQ 20
#define MAXLINE 10000
#define SERV_PORT 6666

int main(int argc, char **argv)
{
	int					listenfd, connfd;
	struct sockaddr_in	cliaddr, servaddr;

	listenfd = socket(AF_INET, SOCK_STREAM, 0);

	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family      = AF_INET;
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	servaddr.sin_port        = htons(SERV_PORT);

	bind(listenfd, (struct sockaddr*) &servaddr, sizeof(servaddr));

	listen(listenfd, LISTENQ);

	int addrSize = sizeof(cliaddr);
	connfd = accept(listenfd, (struct sockaddr*) &cliaddr, &addrSize);
	printf("connected from:%s, port:%d \n\n", inet_ntoa(cliaddr.sin_addr), ntohs(cliaddr.sin_port));

	close(listenfd);	/* close listening socket */

	int epollFd;

	epollFd = epoll_create(256);

	struct epoll_event ev,events[20];

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

    epoll_ctl(epollFd,EPOLL_CTL_ADD,connfd,&ev);

    // stdin = 0
    ev.data.fd=0;
    ev.events=EPOLLIN;
    epoll_ctl(epollFd,EPOLL_CTL_ADD,0,&ev);

	char	sendline[MAXLINE], recvline[MAXLINE];
    while(1){
    	int nfds=epoll_wait(epollFd,events,20,0);
    	for (int i = 0; i < nfds; ++i){
    		if(events[i].data.fd==connfd){
    			int n = read(connfd, recvline, MAXLINE); // TODO: add n == 0
    			fputs(recvline, stdout);
    		}else if(events[i].data.fd==0){
    			fgets(sendline, MAXLINE, stdin);
    			send(connfd, sendline, strlen(sendline), 0);
    		}
    	}
    }

	close(connfd);
	close(epollFd);
	return 0;
}

client

#include <sys/epoll.h>
#include <fcntl.h>
#include <netinet/in.h>    // for sockaddr_in
#include <sys/types.h>    // for socket
#include <sys/socket.h>    // for socket
#include <stdio.h>        // for printf
#include <stdlib.h>        // for exit
#include <string.h>        // for bzero
#include <arpa/inet.h>     // inet_ntoa
#include <unistd.h>

#define SERV_PORT 6666
#define MAXLINE 10000
struct sockaddr_in	servaddr, servaddr1;


int
main(int argc, char **argv)
{
	int					connfd;

	if (argc != 2){
		printf("usage: tcpcli <IPaddress>");
		exit(0);
	}

	connfd = socket(AF_INET, SOCK_STREAM, 0);

	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(SERV_PORT);
	inet_pton(AF_INET, argv[1], &servaddr.sin_addr);

	connect(connfd, (struct sockaddr*) &servaddr, sizeof(servaddr));


	int epollFd;

	epollFd = epoll_create(256);

	struct epoll_event ev,events[20];

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

    epoll_ctl(epollFd,EPOLL_CTL_ADD,connfd,&ev);
    // stdin = 0
    ev.data.fd=0;
    ev.events=EPOLLIN;
    epoll_ctl(epollFd,EPOLL_CTL_ADD,0,&ev);

	char	sendline[MAXLINE], recvline[MAXLINE];
    while(1){
    	int nfds=epoll_wait(epollFd,events,20,0);
    	for (int i = 0; i < nfds; ++i){
    		if(events[i].data.fd==connfd){
    			int n = read(connfd, recvline, MAXLINE);
    			fputs(recvline, stdout);
    		}else if(events[i].data.fd==0){
    			fgets(sendline, MAXLINE, stdin);
    			send(connfd, sendline, strlen(sendline), 0);
    		}
    	}
    }

	close(connfd);
	close(epollFd);
	return 0;
}