#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/socket.h>#include <netinet/in.h>#include <errno.h>#include <netdb.h>#include <arpa/inet.h>#include <unistd.h>#include <sys/time.h>#include <sys/select.h>#define MAXDATASIZE 128#define max(a,b) ((a)>(b)?(a):(b))int main(int argc,char **argv){	int sockfd1,sockfd2,nbytes;	char buf[MAXDATASIZE];	struct sockaddr_in srvaddr1,srvaddr2;	int port1,port2;	int multi=0;	if(argc<3){		printf("usage:./client port1 port2\n");		exit(0);	}	port1=atoi(argv[1]);	port2=atoi(argv[2]);	if(argc==4)		multi=1;	//1.創建網絡端點	sockfd1=socket(AF_INET,SOCK_STREAM,0);	sockfd2=socket(AF_INET,SOCK_STREAM,0);	if(sockfd1==-1||sockfd2==-1){		printf("create socket error\n");		exit(1);	}	//指定服務器地址（本地socket地址采用默認值）	bzero(&srvaddr1,sizeof(srvaddr1));	srvaddr1.sin_family=AF_INET;	srvaddr1.sin_port=htons(port1);		if(inet_aton("127.0.0.1",&srvaddr1.sin_addr)==-1){		printf("addr convert error\n");		exit(1);	}		memcpy(&srvaddr2,&srvaddr1,sizeof(srvaddr1));	srvaddr2.sin_port=htons(port2);	//2.連接服務器	if(connect(sockfd1,(struct sockaddr *)&srvaddr1,sizeof(struct sockaddr))==-1		||connect(sockfd2,(struct sockaddr *)&srvaddr2,sizeof(struct sockaddr))==-1){		printf("connect error\n");		exit(1);	}		//4.接收響應	struct timeval starttime,endtime;		gettimeofday(&starttime,NULL);	printf("start time:%ld\n",starttime.tv_sec);	if(!multi){				if((nbytes=read(sockfd1,buf,MAXDATASIZE))==-1){			printf("read error\n");			exit(1);		}		buf[nbytes]='\0';		gettimeofday(&endtime,NULL);		printf("(%ld) server1 respons:%s\n",endtime.tv_sec,buf);		if((nbytes=read(sockfd2,buf,MAXDATASIZE))==-1){			printf("read error\n");			exit(1);		}		buf[nbytes]='\0';		gettimeofday(&endtime,NULL);		printf("(%ld) server2 respons:%s\n",endtime.tv_sec,buf);	}	else{//多路復用		int fd1_finished=0;		int fd2_finished=0;		while(!fd1_finished||!fd2_finished){			fd_set rdset;			FD_ZERO(&rdset);			if(!fd1_finished);				FD_SET(sockfd1,&rdset);			if(!fd2_finished)				FD_SET(sockfd2,&rdset);			struct timeval tv;			tv.tv_sec=0;			tv.tv_usec=100;			int n=select(max(sockfd1,sockfd2)+1,&rdset,NULL,NULL,&tv);			if(n<=0)				continue;			else{				if(!fd1_finished&&FD_ISSET(sockfd1,&rdset)){					if((nbytes=read(sockfd1,buf,MAXDATASIZE))==-1){						printf("read error\n");						exit(1);					}					buf[nbytes]='\0';					gettimeofday(&endtime,NULL);					printf("(%ld) server1 respons:%s\n",endtime.tv_sec,buf);					fd1_finished=1;				}				if(!fd2_finished&&FD_ISSET(sockfd2,&rdset)){					if((nbytes=read(sockfd2,buf,MAXDATASIZE))==-1){						printf("read error\n");						exit(1);					}					buf[nbytes]='\0';					gettimeofday(&endtime,NULL);					printf("(%ld) server2 respons:%s\n",endtime.tv_sec,buf);					fd2_finished=1;				}			}		}	}	//關閉socket	close(sockfd1);	close(sockfd2);	return 0;}