<分区>
当我运行这个程序时，我输入了一个 ip 地址和服务器端口作为输入。然而，在此之后程序要求我“请输入消息:”。但是，在键入我的消息后，按 ctrl-D 不会执行任何操作。该程序仍然从 STDIN 读取。如何指示我正在键入的消息的结尾？
这是我正在使用的程序:
/*
* echoclient.c - A simple connection-based client
* usage: echoclient <host> <port>
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#define BUFSIZE 1024
/*
* error - wrapper for perror
*/
void error(char *msg) {
perror(msg);
exit(0);
}
int main(int argc, char **argv) {
int sockfd, portno, n;
struct sockaddr_in serveraddr;
struct hostent *server;
char *hostname;
char buf[BUFSIZE];
/* check command line arguments */
if (argc != 3) {
fprintf(stderr,"usage: %s <hostname> <port>\n", argv[0]);
exit(0);
}
hostname = argv[1];
portno = atoi(argv[2]);
/* socket: create the socket */
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0)
error("ERROR opening socket");
/* gethostbyname: get the server's DNS entry */
server = gethostbyname(hostname);
if (server == NULL) {
fprintf(stderr,"ERROR, no such host as %s\n", hostname);
exit(0);
}
/* build the server's Internet address */
bzero((char *) &serveraddr, sizeof(serveraddr));
serveraddr.sin_family = AF_INET;
bcopy((char *)server->h_addr,
(char *)&serveraddr.sin_addr.s_addr, server->h_length);
serveraddr.sin_port = htons(portno);
/* connect: create a connection with the server */
if (connect(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0)
error("ERROR connecting");
/* get message line from the user */
printf("Please enter msg: ");
bzero(buf, BUFSIZE);
fgets(buf, BUFSIZE, stdin);
/* write: send the message line to the server */
n = write(sockfd, buf, strlen(buf));
if (n < 0)
error("ERROR writing to socket");
/* read: print the server's reply */
bzero(buf, BUFSIZE);
n = read(sockfd, buf, BUFSIZE);
if (n < 0)
error("ERROR reading from socket");
printf("Echo from server: %s", buf);
close(sockfd);
return 0;
}