c语言socket编程 与服务器长连接的客户端程序

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

#define MAXBUF 1024

int main(int argc, char **argv)
{
int sockfd, len;
struct sockaddr_in dest;
char buffer[MAXBUF];
fd_set rfds;
struct timeval tv;
int retval, maxfd = -1;

if (argc != 3) {
printf
("error！the right format should be：\n\t\t%s IP port\n\t eg:\t%s 127.0.0.1 80\n",
argv[0], argv[0]);
exit(0);
}

if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
perror("Socket");
exit(errno);
}


bzero(&dest, sizeof(dest));
dest.sin_family = AF_INET;
dest.sin_port = htons(atoi(argv[2]));
if (inet_aton(argv[1], (struct in_addr *) &dest.sin_addr.s_addr) == 0) {
perror(argv[1]);
exit(errno);
}


if (connect(sockfd, (struct sockaddr *) &dest, sizeof(dest)) != 0) {
perror("Connect ");
exit(errno);
}

printf
("\n Ready to start chatting. Direct input message and enter to send messages to the server\n");
while (1) {

FD_ZERO(&rfds);

FD_SET(0, &rfds);
maxfd = 0;

FD_SET(sockfd, &rfds);
if (sockfd > maxfd)
maxfd = sockfd;

_sec = 1;
_usec = 0;

retval = select(maxfd + 1, &rfds, NULL, NULL, &tv);
if (retval == -1) {
printf("Will exit and the select is error！ %s", strerror(errno));
break;
} else if (retval == 0) {
/* printf
("No massage comes, no buttons, continue to wait ...\n"); */
continue;
} else {
if (FD_ISSET(sockfd, &rfds)) {

bzero(buffer, MAXBUF + 1);

len = recv(sockfd, buffer, MAXBUF, 0);
if (len > 0)
printf
("Successfully received the message: '% s',% d bytes of data\n",
buffer, len);
else {
if (len < 0)
printf
("Failed to recerve the message! The error code is %d, error message is'%s'\n",
errno, strerror(errno));
else
printf("Chat to terminate！\n");
break;
}
}
if (FD_ISSET(0, &rfds)) {

bzero(buffer, MAXBUF + 1);
fgets(buffer, MAXBUF, stdin);
if (!strncasecmp(buffer, "quit", 4)) {
printf("Own request to terminate the chat！\n");
break;
}

len = send(sockfd, buffer,

strlen(buffer) - 1, 0);
if (len < 0) {
printf
("Message '% s' failed to send! The error code is% d, error message '% s'\n",
buffer, errno, strerror(errno));
break;
} else
printf
("News:% s \ t send, sent a total of% d bytes！\n",
buffer, len);
}
}
}

close(sockfd);
return 0;
}