http://blog.csdn.net/libinbin_1014/article/details/50096187

Epoll 的tcp通信代碼（服務器+客戶端）

/*
gcc -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -I${ORACLE_HOME}/rdbms/public -I${ORACLE_HOME}/rdbms/demo -L${ORACLE_HOME}/lib -lclntsh  -pthread -o epoll_server epoll_server.c
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <sys/epoll.h>
#include <sys/time.h>
#include <sys/resource.h>#define MAXBUF 1024
#define MAXEPOLLSIZE 10000/*
setnonblocking - 設置句柄為非阻塞方式
*/
int setnonblocking(int sockfd)
{if (fcntl(sockfd, F_SETFL, fcntl(sockfd, F_GETFD, 0)|O_NONBLOCK) == -1) {return -1;}return 0;
}/*
handle_message - 處理每個 socket 上的消息收發
*/
int handle_message(int new_fd)
{char buf[MAXBUF + 1];char sendbuf[MAXBUF+1];int len;/* 開始處理每個新連接上的數據收發 */bzero(buf, MAXBUF + 1);/* 接收客戶端的消息 */len = recv(new_fd, buf, MAXBUF, 0);if (len > 0){printf("%d接收消息成功:'%s'，共%d個字節的數據/n",new_fd, buf, len);}else {if (len < 0)printf("消息接收失敗！錯誤代碼是%d，錯誤信息是'%s'/n",errno, strerror(errno));elseprintf("客戶端%d退出!/n",new_fd);return -1;}/* 處理每個新連接上的數據收發結束 */return len;
}int main(int argc, char **argv)
{int listener, new_fd, nfds, n, ret;struct epoll_event ev;int kdpfd, curfds;socklen_t len;struct sockaddr_in my_addr, their_addr;unsigned int myport, lisnum;struct epoll_event events[MAXEPOLLSIZE];struct rlimit rt;if (argc>1)myport = atoi(argv[1]);elsemyport = 1234;if (argc>2)lisnum = atoi(argv[2]);elselisnum = 10;/* 設置每個進程允許打開的最大文件數 */rt.rlim_max = rt.rlim_cur = MAXEPOLLSIZE;if (setrlimit(RLIMIT_NOFILE, &rt) == -1) {perror("setrlimit");exit(1);}else printf("設置系統資源參數成功！/n");/* 開啟 socket 監聽 */if ((listener = socket(PF_INET, SOCK_STREAM, 0)) == -1) {perror("socket");exit(1);} elseprintf("socket 創建成功！/n");/*設置socket屬性，端口可以重用*/int opt=SO_REUSEADDR;setsockopt(listener,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));/*設置socket為非阻塞模式*/setnonblocking(listener);bzero(&my_addr, sizeof(my_addr));my_addr.sin_family = PF_INET;my_addr.sin_port = htons(myport);if (argc>3)my_addr.sin_addr.s_addr = inet_addr(argv[3]);elsemy_addr.sin_addr.s_addr = INADDR_ANY;if (bind(listener, (struct sockaddr *) &my_addr, sizeof(struct sockaddr))== -1) {perror("bind");exit(1);}elseprintf("IP 地址和端口綁定成功/n");if (listen(listener, lisnum) == -1) {perror("listen");exit(1);} elseprintf("開啟服務成功！/n");/* 創建 epoll 句柄，把監聽 socket 加入到 epoll 集合里 */kdpfd = epoll_create(MAXEPOLLSIZE);len = sizeof(struct sockaddr_in);ev.events = EPOLLIN | EPOLLET;ev.data.fd = listener;if (epoll_ctl(kdpfd, EPOLL_CTL_ADD, listener, &ev) < 0) {fprintf(stderr, "epoll set insertion error: fd=%d/n", listener);return -1;} elseprintf("監聽 socket 加入 epoll 成功！/n");curfds = 1;while (1) {/* 等待有事件發生 */nfds = epoll_wait(kdpfd, events, curfds, -1);if (nfds == -1) {perror("epoll_wait");break;}/* 處理所有事件 */for (n = 0; n < nfds; ++n) {if (events[n].data.fd == listener) {new_fd = accept(listener, (struct sockaddr *) &their_addr,&len);if (new_fd < 0) {perror("accept");continue;elseprintf("有連接來自于：%s:%d，分配的 socke為:%d/n",inet_ntoa(their_addr.sin_addr), ntohs(their_addr.sin_port), new_fd);setnonblocking(new_fd);ev.events = EPOLLIN | EPOLLET;ev.data.fd = new_fd;if (epoll_ctl(kdpfd, EPOLL_CTL_ADD, new_fd, &ev) < 0) {fprintf(stderr, "把 socket '%d' 加入 epoll 失敗！%s/n",new_fd, strerror(errno));return -1;}curfds++;} else {ret = handle_message(events[n].data.fd);if (ret < 1 && errno != 11) {if(epoll_ctl(kdpfd, EPOLL_CTL_DEL, events[n].data.fd,&ev) < 0){fprintf(stderr, "把 socket '%d' 從 epoll 刪除失敗！%s/n",events[n].data.fd, strerror(errno));}curfds--;close(events[n].data.fd);}}}}close(listener);return 0;
}

tcp客戶端client.c:#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <sys/select.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>#define MAXLINE 1024
char sendhead[MAXLINE];int main(int argc , char* argv[])
{int sockfd;struct sockaddr_in servaddr;char *info="cxt";int   maxfdp1, stdineof;fd_set  rset;char  recvbuf[MAXLINE],tmp[128],sendbuf[MAXLINE];int   n,len,fd;if(argc!=3){printf("useage:client address port ");exit(0);}if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1  ){perror("socket");exit(1);}printf("%s connect server/n",info);bzero(&servaddr,sizeof(servaddr));servaddr.sin_family=AF_INET;servaddr.sin_port=htons(atoi(argv[2]));inet_pton(AF_INET,argv[1],&servaddr.sin_addr);if( ( connect(sockfd,(struct sockaddr*)&servaddr,sizeof(servaddr))  )<0){perror("connect");exit(1);}send(sockfd,info,strlen(info),0);for ( ; ; ) {FD_ZERO(&rset);FD_SET(sockfd, &rset);FD_SET(0, &rset); maxfdp1=sockfd+1;if((select(maxfdp1, &rset, NULL, NULL, NULL) )<=0){perror("select");}else{if (FD_ISSET(0,&rset)){fgets(sendbuf, MAXLINE, stdin);n=send(sockfd,sendbuf,strlen(sendbuf)-1,0);if(n>0)printf("send: %s",sendbuf);elseprintf("send: %s error,the erro cause is %s:%s/n",sendbuf,errno,strerror(errno));bzero(sendbuf,strlen(sendbuf));}if (FD_ISSET(sockfd, &rset)) { /* socket is readable */n=recv(sockfd, recvbuf, MAXLINE,0) ;if(n<0) {perror("str_cli: server terminated prematurely");}else if(n==0){printf("sever shutdown!");exit(-1);}//recvbufrecvbuf[n]='/0';printf("receive :%s/n",recvbuf);fflush(stdout);bzero(recvbuf,strlen(recvbuf));}}}exit(0);
}