/* * server * tcp * 文字聊天 */#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>#define MAXBUF 1024int main(int argc, char **argv){	int sockfd, new_fd;	socklen_t len;	struct sockaddr_in my_addr, their_addr;	unsigned int myport, lisnum;	char buf[MAXBUF + 1];		//設端口號	if (argv[1])		myport = atoi(argv[1]);	else		myport = 7838;		//設最大連接個數	if (argv[2])		lisnum = atoi(argv[2]);	else		lisnum = 2;		if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) {		perror("socket");		exit(1);	}		bzero(&my_addr, sizeof(my_addr));	my_addr.sin_family = PF_INET;	my_addr.sin_port = htons(myport);	if (argv[3])		my_addr.sin_addr.s_addr = inet_addr(argv[3]);	else		my_addr.sin_addr.s_addr = INADDR_ANY;			if (bind(sockfd, (struct sockaddr *) &my_addr, sizeof(struct sockaddr))== -1) {		perror("bind");		exit(1);	}		if (listen(sockfd, lisnum) == -1) {		perror("listen");		exit(1);	}		while (1) {		printf("\n----等待新的連接到來開始新一輪聊天……\n");		len = sizeof(struct sockaddr);		if ((new_fd =	accept(sockfd, (struct sockaddr *) &their_addr,&len)) == -1) {			perror("accept");			exit(errno);		} 		else			printf("server: got connection from %s, port %d, socket %d\n",					inet_ntoa(their_addr.sin_addr),					ntohs(their_addr.sin_port), new_fd);			/* 開始處理每個新連接上的數據收發 */		while (1) {			/* 發消息給客戶端 */			bzero(buf, MAXBUF + 1);			printf("請輸入要發送給對方的消息：");			fgets(buf, MAXBUF, stdin);	//輸入			if (!strncasecmp(buf, "quit", 4)) {//quit				printf("自己請求終止聊天！\n");				break;			}			len = send(new_fd, buf, strlen(buf) - 1, 0);//發送			if (len > 0)				printf("消息:%s\t發送成功，共發送了%d個字節！\n",buf, len);			else {				printf("消息'%s'發送失敗！錯誤代碼是%d，錯誤信息是'%s'\n",buf, errno, strerror(errno));				break;			}			bzero(buf, MAXBUF + 1);			/* 接收客戶端的消息 */			len = recv(new_fd, buf, MAXBUF, 0);			if (len > 0)				printf("接收消息成功:'%s'，共%d個字節的數據\n",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));				else					printf("對方退出了，聊天終止\n");				break;			}		}//while		close(new_fd);		/* 處理每個新連接上的數據收發結束 */	}//while		close(sockfd);		return 0;}/* * fgets(buf, MAXSIZE, stdin); * strncasecmp(buf, "quit", 4); */