Thread: receiving problems in network chat client

i am coding a network chat client, an di am having trouble with the receive part.

i'm not sure how to get whats received and print it out onto the screen, i think i have to get whats received and place it in the receive buffer then print it to the screen and clare the buffer. but i am not sure how to do this

Code:

	for (;;) 
	{
		gets(sendBuffer);								//takes input from keyboard
		
		if (strcmp(sendBuffer, "quit") == 0)			//if quit was typed then end client
		{				
			break;
		}

		unsigned long messagelength = strlen(sendBuffer);		//get size of message

		messagelength = htonl(messagelength);					//fix byte ordering

		if ((nbytes = send(mysocket, (char*)&messagelength, sizeof(messagelength), 0)) == SOCKET_ERROR) 
		{
			cout << "Send Failed!" << endl;						//send the message size
		}

		messagelength = ntohl(messagelength);					//refix byte ordering

		if ((nbytes = send(mysocket, sendBuffer, messagelength, 0)) == SOCKET_ERROR) 
		{
			cout << "Send Failed!" << endl;						//send actual message
		}

		
		gets(receiveBuffer);
	
		unsigned long messagesize = strlen(receiveBuffer);

		messagesize = htonl(messagesize);

		if ((nbytes = recv(mysocket, (char*)&messagesize, sizeof(messagesize), 0)) == SOCKET_ERROR) 
		{
			cout << "Receive Failed!" << endl;						
		}

		messagesize = ntohl(messagesize);

		if ((nbytes = recv(mysocket, receiveBuffer, messagesize, 0)) == SOCKET_ERROR) 
		{
			cout << "Receive Failed!" << endl;						
		}
	}

please give me an idea

ok got it to kinda work now, but i can't get the buffer to empty after it prints out the message so i end up with a load of crap printed out

Code:

	for (;;) 
	{
		gets(sendBuffer);								//takes input from keyboard
		
		if (strcmp(sendBuffer, "quit") == 0)			//if quit was typed then end client
		{				
			break;
		}

		unsigned long messagelength = strlen(sendBuffer);		//get size of message

		messagelength = htonl(messagelength);					//fix byte ordering

		if ((nbytes = send(mysocket, (char*)&messagelength, sizeof(messagelength), 0)) == SOCKET_ERROR) 
		{
			cout << "Send Failed!" << endl;						//send the message size
		}

		messagelength = ntohl(messagelength);					//refix byte ordering

		if ((nbytes = send(mysocket, sendBuffer, messagelength, 0)) == SOCKET_ERROR) 
		{
			cout << "Send Failed!" << endl;						//send actual message
		}

		recv(mysocket,receiveBuffer,messagelength,0);
		cout << " " << receiveBuffer << endl;
		memset( (char *) &receiveBuffer, 0,sizeof(sendBuffer));

my send and receive loop as it is atm

One solution is to allocate a temporary buffer and copy only the data received. Output the temporary buffer and then deallocate. messagelength is the size.

Kuphryn

i have figured the problem is that i don't get the full message printed out from the buffer, not sure if its reading too fast or what

any ideas at all?

I don't think you need the byte ordering calls - you could remove all of those.

One problem is that you're treating receiveBuffer as null-terminated string, which it isn't. The send call sends strlen(input) bytes, i.e. it doesn't send the null terminator. You'll need to manually terminate your received string.

Also, your code isn't reliable. When you call recv you might not receive the number of bytes you specify as the buffer size - recv is allowed to return when there's anything from a single byte available to read. Read up on TCP/IP.