Winsocket keeps disconnecting as soon as it connects

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I am working of a DLL for a test and i keep getting socket errors.

i am trying to to connect to a server localhost, when it connects i close the server and i want it to continue to try and connect but as i open the server again it keeps disconnecting

C++

bool ISExit = false;
bool Disconnect = false;
void Networking(){
	WSAData data;
	int wsResult = WSAStartup(MAKEWORD(2, 2), &data);
	if (wsResult != 0)
	{
		std::cout << "Can't start Winsock, Err #" << wsResult << std::endl;
		return;
	}

	// Create socket
	SOCKET sock = socket(AF_INET, SOCK_STREAM, 0);
	if (sock == INVALID_SOCKET)
	{
		std::cout << "Can't create socket, Err #" << WSAGetLastError() << std::endl;
		WSACleanup();
		return;
	}

	// Fill in a hint structure
	sockaddr_in hint;
	hint.sin_family = AF_INET;
	hint.sin_port = htons(port);
	inet_pton(AF_INET, ipAddress.c_str(), &hint.sin_addr);

	// Connect to server
	int connResult = connect(sock, (sockaddr*)&hint, sizeof(hint));
	if (connResult == SOCKET_ERROR)
	{
		std::cout << "Can't connect to server, Err #" << WSAGetLastError() << std::endl;
		closesocket(sock);
		WSACleanup();
		return;
	}

	// while loop to send and receive data
	while (!IsExit)
	{
		std::cout << "IsExit = " << std::boolalpha << IsExit << std::endl;
		std::cout << "Disconnect = " << std::boolalpha << Disconnect << std::endl;
		std::string output{ GetData(sock) };
		std::cout << output;
		if (output == "exit\n") {
			IsExit = true;
		}
		if (Disconnect) {
			IsExit = true;
		}
	}

	// Gracefully close down everything
	closesocket(sock);
	WSACleanup();
}

int main(){
    while(true){
        Networking();
    }
}

What I have tried:

i have tried closing the sock and reopening it but that didn't work and i tried to see why and for the life of me i can't see whats wrong with my code.

right i belive the problem is here

std::string GetData(SOCKET sock) {
	char buf[1024];

	int bytesReceived = recv(sock, buf, 1024, 0);
	if (bytesReceived == SOCKET_ERROR)
		std::cout << "SOCKET ERROR (GETDATA())\n";
		IsExit = true;

	return std::string(buf, 0, bytesReceived);
}

Posted 24-Apr-20 18:33pm

WOLF 2018

Updated 25-Apr-20 3:41am

v4

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Comments

Shao Voon Wong 25-Apr-20 6:00am

What is the console output? Disconnect might be set to true by default?

WOLF 2018 25-Apr-20 6:32am

disconnect is set to false

[no name] 25-Apr-20 8:33am

How is about IsExit? I don't see that you initialize it to false...

WOLF 2018 25-Apr-20 8:47am

well it is set to false

bool IsExit = false;
while (!IsExit)
{
std::string input;
std::getline(std::cin, input);
SendData(sock, input);
std::string output{ GetData(sock) };
std::cout << output << std::endl;
if (output == "exit\n") {
IsExit = true;
}
if (Disconnect) {
IsExit = true;
}
}

[no name] 25-Apr-20 8:49am

Ok, I only don't see that in the code you posted in the question ;)

[no name] 25-Apr-20 8:55am

Now in the updated code in the question you still don't set IsExit to false and therefore when you call Networking the second time it will not execute the loop...

WOLF 2018 25-Apr-20 9:11am

thats true, i will give thats a try

WOLF 2018 25-Apr-20 9:14am

ok i tried adding that at the start of Networking

with

IsExit = false;
Disconnect = false;

and it does the samething

2 solutions

Solution 2

Because IsExit is global (whyever) you need to set it to false each time before the loop, otherwhise IsExit reamains true after calling Networking once:

...
// while loop to send and receive data
IsExit= false;
while (!IsExit)
{
   ...
}

Posted 25-Apr-20 3:15am

User 11060979

Comments

WOLF 2018 25-Apr-20 9:16am

i tried that and it still does the samething

[no name] 25-Apr-20 9:20am

Strange. So I think you need to debug your code to find the reason.

WOLF 2018 25-Apr-20 9:23am

because its a DLL i am unable to debug it in VS 2019

WOLF 2018 25-Apr-20 9:18am

this is what i get from the server

Ncat: Version 5.59BETA1 ( http://nmap.org/ncat )
Ncat: Listening on 0.0.0.0:3000
Ncat: Connection from 127.0.0.1:53169.
hello
Ncat: Version 5.59BETA1 ( http://nmap.org/ncat )
Ncat: Listening on 0.0.0.0:3000
Ncat: Connection from 127.0.0.1:53170.

and the client output is

Can't connect to server, Err #10061
Can't connect to server, Err #10061
IsExit = false
Disconnect = false
hello
IsExit = false
Disconnect = false
SOCKET ERROR (GETDATA()) // thats because i disconnected

[no name] 25-Apr-20 9:23am

Looks like I misunderstand you, I thought first run of Networking was successful. So can you confirm, even first run of Networking fails?

WOLF 2018 25-Apr-20 9:30am

well it was, but now i have been changing the code it not anymore

WOLF 2018 25-Apr-20 9:35am

ok i have update

IsExit = false
hello
Exited Loop // It exits loop

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WOLF 2018 · Accepted Answer · 2020-04-25T03:42:00

Ok i found the problem

std::string GetData(SOCKET sock) {
	char buf[1024];

	int bytesReceived = recv(sock, buf, 1024, 0);
	if (bytesReceived == SOCKET_ERROR)
		std::cout << "SOCKET ERROR (GETDATA())\n";
		IsExit = true;

	return std::string(buf, 0, bytesReceived);
}

It works when i fix the {}

std::string GetData(SOCKET sock) {
	char buf[1024];

	int bytesReceived = recv(sock, buf, 1024, 0);
	if (bytesReceived == SOCKET_ERROR) {
		std::cout << "SOCKET ERROR (GETDATA())\n";
		IsExit = true;
	}

	return std::string(buf, 0, bytesReceived);
}

Thanks 0x0aAA for the help