Reply to Struct über connected Socket senden on Sun, 09 Jul 2006 11:06:20 GMT

simube — Sun, 09 Jul 2006 11:06:20 GMT

I've a problem with sending a structure of the type pkt over my connected socket. I've not too much experience in programming C/C++. Thus, I've no clue what the problem could be. I've spent quite a lot of time in this but didn't got the problem. I'm using sendmsg() and recvmsg(). Both seems to work. But when I try to access the received data, I recognize that the results are completely wrong (probably initial values instead of received data). Can anybody tell me my mistake? Would be great!

CLIENT:

int main ( int argc, int argv[] )
{
	struct msghdr msg;
	struct iovec iov[1];
	struct pkt {
		int a;
		int b;
	} p ;
	p.a = 123;
	p.b = 234;

	iov[0].iov_base = &p;
	iov[0].iov_len = sizeof(p);

	try
	{
		ClientSocket client_socket ( "localhost", 30000 );

		std::string reply;
		std::string message;

		try
		{
			msg.msg_iov = iov ;
			msg.msg_iovlen = 1 ;
			msg.msg_name = NULL ;
			msg.msg_namelen = 0 ;
			msg.msg_control = (caddr_t) &p ;
  			msg.msg_controllen = sizeof (struct pkt) ;
  			msg.msg_flags = 0 ;

			client_socket << msg ;
		}

...

SERVER:

int main ( int argc, int argv[] )
{
	struct iovec iov[1]; 
	struct msghdr inmessage;
	char * buffer_rcv;

	struct pkt {
		int a;
		int b;
	} inp ;

	try
    {
		// Create the socket
		ServerSocket server ( 30000 ) ;

		while ( true )
		{
			ServerSocket new_sock ;
			server.accept ( new_sock ) ;

			try
			{
				while ( true )
				{
					buffer_rcv = (char*)memset(&inmessage, 0, sizeof(inmessage));

					iov[0].iov_base = buffer_rcv; 
					iov[0].iov_len = sizeof(inmessage);

					inmessage.msg_iov = iov; 
					inmessage.msg_iovlen = 1; 
					inmessage.msg_name = NULL; 
					inmessage.msg_namelen = 0; 
					inmessage.msg_control = (caddr_t) &inp; 
					inmessage.msg_controllen = sizeof (struct pkt); 
					inmessage.msg_flags = 0;

					new_sock >> inmessage;

					std::cout << "inp.a: '" << inp.a << "'" << endl;  // returns 134522371
					std::cout << "inp.b: '" << inp.b << "'" << endl;  // 134522371 too

....

Vielen Dank. Grüsse, Simu