reading TCP port

[tneva82]

Not working at all. I can open the port without errors, I get client connected to it but reading results in -1 as a result.


IPaddress readAddress;
TCPsocket readSocket;

Just the address of server and the socket it's going to use for receiving.


int serverNetwork::openPort(int readPort) {

if(SDLNet_ResolveHost(&readAddress, NULL, readPort) !=0) {
printf("Address resolving failed!");
exit(1);
}

readSocket=SDLNet_TCP_Open(&readAddress);

if(!readSocket) {
printf("SDLNet_TCP_Open: %s\n", SDLNet_GetError());
exit(2);
}
}

Resolve servers address and open socket to it. As far as I can see no real difference to example codes. Just names.


int serverNetwork::receiveData(char *answer, int maxLength) {
return result=SDLNet_TCP_Recv(readSocket, answer, maxLength);
}

And here's where issues seems to be. Result is constantly -1. How What's causing that? SDL_Net doc's say just that it's error. Nothing about what sort of error.

And here's the code which uses class of which above are part of.


serverNetwork *server=new serverNetwork();
char *answer=new char[120];
int count;
bool running=TRUE;
server->openPort(4500);
printf("Server running\n");
while(running) {
server->checkForConnections();
count=server->receiveData(answer, 120);
printf("%i\n", count); // prints -1 every time.


Anybody could point the(probably obvious) error I'm making?

[johnl]

It's hard to say because I can't see some of the relevant code.

I would wager this:


server->checkForConnections();
count=server->receiveData(answer, 120);


might be wrong. what does server->checkForConnections() do? You need to accept() a connection before you can recv() from it.

I am not familiar with the SDL stuff so I can't really say; you might find it worthwhile to change your code to include a perror() statement like so, which will display why exactly the receive failed.



int serverNetwork::receiveData(char *answer, int maxLength) {
int result;
if ((result = SDLNet_TCP_Recv(readSocket, answer, maxLength)) == -1) {
perror("Error receiving data");
}

return result;
}

[tneva82]

[QUOTE=johnlmight be wrong. what does server->checkForConnections() do? You need to accept() a connection before you can recv() from it.[/quote]

Right. I forgot to mention that code. checkForConnections precicely calls accept() function. And I added it to return boolean to see wether connection is accepted. So if accept() returns non-NULL value checkForConnections return true(otherwise false) so connection is established as far as I can tell. It doesn't now even try to read data until checkForConnections returns true.

[johnl]

What are you doing with the return value of accept() ? You need to recv() on the socket returned from accept(), not the original listening socket.

[tneva82]

What are you doing with the return value of accept() ? You need to recv() on the socket returned from accept(), not the original listening socket.

Ah the socket is stored in the class which is then used by the sendData. I use the return value simply to check that there was a connection made.

[tneva82]

Right. Problem solved. What I messed up was that I didn't think up that I should use the socket given by TCP_Accept to both sending AND listening. I thought I would listen the port I had opened!

Annoying logical error but thankfully solved one!