socket服务端客户端简单程序

/******* 服务器程序 (server.c) ************/ #include "stdio.h" #include "stdlib.h" #include "errno.h" #include "sys/types.h" #include "sys/socket.h" #include "unistd.h" #include "netinet/in.h" #include "netdb.h" int main(int argc,char *argv[]) { int sockfd,new_fd; struct sockaddr_in server_addr; struct sockaddr_in client_addr; int sin_size,portnumber; char hello[]="Hello! Are You Fine? "; if ( argc!=2 ) { fprintf(stderr,"Usage:%s portnumbera ",argv[0]); exit(1); } if((portnumber=atoi(argv[1]))<0) { fprintf(stderr,"Usage:%s portnumbera ",argv[0]); exit(1); } /* 服务器端开始建立socket描述符 */ if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1) { fprintf(stderr,"Socket error:%s a",strerror(errno)); exit(1); } /* 服务器端填充 sockaddr结构 */ bzero(&server_addr,sizeof(struct sockaddr_in)); server_addr.sin_family=AF_INET; server_addr.sin_addr.s_addr=htonl(INADDR_ANY); server_addr.sin_port=htons(portnumber); /* 捆绑sockfd描述符 */ if(bind(sockfd,(struct sockaddr *)(&server_addr),sizeof(struct sockaddr))==-1) { fprintf(stderr,"Bind error:%s a",strerror(errno)); exit(1); } /* 监听sockfd描述符 */ if(listen(sockfd,5)==-1) { fprintf(stderr,"Listen error:%s a",strerror(errno)); exit(1); } while(1) { /* 服务器阻塞,直到客户程序建立连接 */ sin_size=sizeof(struct sockaddr_in); if((new_fd=accept(sockfd,(struct sockaddr *)(&client_addr),&sin_size))==-1) { fprintf(stderr,"Accept error:%s a",strerror(errno)); exit(1); } fprintf(stderr,"Server get connection from %s ",inet_ntoa(client_addr.sin_addr)); if(write(new_fd,hello,strlen(hello))==-1) { fprintf(stderr,"Write Error:%s ",strerror(errno)); exit(1); } close(new_fd); } close(sockfd); exit(0); }