我正在使用Ubuntu 12.04 32位版本我编写了一个程序来从TCP客户端接收XML文件 . 同一程序也通过unix域套接字从另一个进程接收数据 . 为此我使用poll()系统调用 .
我的问题是,有时我没有正确地获取XML数据,或者有时也没有得到它 . 但由于我使用的是TCP,如果有数据丢失,客户端就会知道 . 但是客户没有显示任何错误 . 有人可以告诉我为什么会这样吗?
我可以提供一些代码:
int config_server_tcp(int port)
{
int sockfd = -1;
struct sockaddr_in my_addr; // my address information
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
perror("socket() failed.");
}
else
{
my_addr.sin_family = AF_INET;
my_addr.sin_port = htons(port);
my_addr.sin_addr.s_addr = htonl(INADDR_ANY); // automatically fill with my IP
memset(&(my_addr.sin_zero), 0, 8); // zero the rest of the struct
if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1)
{
perror("bind() failed.");
}
else
{
if (listen (sockfd, 8) == -1)
{
perror("listen() failed.");
}
}
}
return sockfd;
}
int send_to_tcp_server(unsigned char * message, int size, char * server_ip, int port)
{
int sockfd;
struct sockaddr_in their_addr;
int numbytes = -1;
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
perror("socket() failed.");
}
else
{
their_addr.sin_family = AF_INET;
their_addr.sin_port = htons(port);
their_addr.sin_addr.s_addr=inet_addr(server_ip);
memset(&(their_addr.sin_zero), '\0', 8); // zero the rest of the struct
if (connect(sockfd, (struct sockaddr *)&their_addr, sizeof (their_addr)) == -1)
{
perror("connect() failed.");
}
else
{
if ((numbytes=send(sockfd , message, size, 0)) == -1)
{
printf ("Sending failed.\n");
}
}
close (sockfd);
}
return numbytes;
}
void process_tcp (int sock)
{
struct sockaddr_in their_addr; // talker's address information
int received;
socklen_t addr_len;
char buffer[BUFF_SIZE];
addr_len = sizeof (their_addr);
int clientfd = accept (sock, (struct sockaddr *)&their_addr, &addr_len);
if (clientfd == -1)
{
perror("accept() failed.");
}
else
{
do
{
received = recv(clientfd, buffer, BUFF_SIZE, 0);
if (received == -1)
{
perror("recv() failed.");
break;
}
else
{
//do something
}
}
while (received != 0);
close (clientfd);
}
}
进程TCP函数在循环中调用
1 回答
这个错误几乎可以肯定是你没有展示的代码,根据你的XML-over-TCP协议组装应用程序级消息的代码 . 这是一种方法:
请注意,缺少大量错误检查 .