我刚开始接触linux下的socket编程，边抄边理解udp socket编程，我的疑问是server不指定IP地址，client的目标IP地址是127.0.0.1，这样就可以通信吗？在同一主机下是不是不能测试？如果server默认绑定本机的IP 地址，那么开启server后，在浏览器中输入127.0.0.1:(相应端口) 也可以得到数据？我的程序如下，没有跑起来，其实我觉得我不会测试，不知道本质所以会有细节漏掉。（使用的系统是ubuntu 11.10 ，编译器GCC ，分别在同一主机下的两个终端中运行生成的.out文件。）提前感谢大家的回答，不管多少，您的回答让一个初学者非常暖心～～
服务器程序
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#include<stdio.h>#include<netinet/in.h>#include<arpa/inet.h>#include<unistd.h>#include<sys/types.h>#include<sys/socket.h>#define lport 4567int main(){ int mysock,len; struct sockaddr_in addr; int i=0; char msg[256]; int addr_len; if((mysock=socket(AF_INET,SOCK_DGRAM,0))<0) { perror("error"); exit(1); } else { printf("socket created.
"); printf("socket ID: %d
",mysock); } addr_len=sizeof(struct sockaddr_in); bzero(&addr,sizeof(addr)); addr.sin_family=AF_INET; addr.sin_port=htons(lport); addr.sin_addr.s_addr=htonl(INADDR_ANY); if(bind(mysock,&addr,sizeof(addr))<0) { perror("connect"); exit(1); } else { printf("bind ok.
"); printf("local port: %d
",lport); } while(1) { bzero(msg,sizeof(msg)); len=recvfrom (mysock,msg,sizeof(msg),0,&addr,&addr_len); printf("%d: ",i); i++; printf("message form: %s
",inet_ntoa(addr.sin_addr)); printf("message: %s
",msg); sendto(mysock,msg,len,0,&addr,addr_len); } return 0;} |
客户机程序：
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#include<stdio.h>#include<netinet/in.h>#include<arpa/inet.h>#include<unistd.h>#include<fcntl.h>#include<sys/stat.h>#include<sys/types.h>#include<sys/socket.h>#define rport 4567#define rip "127.0.0.1"int main(){ int s,len; struct sockaddr_in addr; int addr_len; char msg[256]; int i=0; if((s=socket(AF_INET,SOCK_DGRAM,0))<0) { perror("error"); exit(1); } else { printf("socket created.
"); printf("socket id: %d
",s); printf("romote ip: %s
",rip); printf("remote port: %d
",rport); } len=sizeof(struct sockaddr_in); bzero(&addr,sizeof(addr)); addr.sin_family=AF_INET; addr.sin_port=htons(rport); addr.sin_addr.s_addr=inet_addr(rip); while(1) { bzero(msg,sizeof(msg)); len=read(STDIN_FILENO,msg,sizeof(msg)); sendto(s,msg,len,0,&addr,addr_len); printf("
Input message: %s
",msg); len=recvfrom(s,msg,sizeof(msg),0,&addr,&addr_len); printf("%d :",i); i++; printf("received message: %s
",msg); } return 0;} |