Unable to connect to the server - windows sockets

Question

//////socket connector method////
bool SocketConnecter::connect(const std::string& ip, size_t port)
size_t uport = htons(port);
std::string sPort = toString(uport);
// Resolve the server address and port
const char* pTemp = ip.c_str();
iResult = getaddrinfo(pTemp, sPort.c_str(), &hints, &result); // was DEFAULT_PORT
if (iResult != 0) {
Verbose::show("\n -- getaddrinfo failed with error: " + toString(iResult), always);
return false;
// Attempt to connect to an address until one succeeds
for (ptr = result; ptr != NULL; ptr = ptr->ai_next) {
char ipstr[INET6_ADDRSTRLEN];
void *addr;
char *ipver;
// get pointer to address - different fields in IPv4 and IPv6:
if (ptr->ai_family == AF_INET) { // IPv4
struct sockaddr_in *ipv4 = (struct sockaddr_in *)ptr->ai_addr;
addr = &(ipv4->sin_addr);
ipver = "IPv4";
else { // IPv6
struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)ptr->ai_addr;
addr = &(ipv6->sin6_addr);
ipver = "IPv6";
// convert the IP to a string and print it:
inet_ntop(ptr->ai_family, addr, ipstr, sizeof ipstr);
printf("\n %s: %s", ipver, ipstr);
// Create a SOCKET for connecting to server
socket_ = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
if (socket_ == INVALID_SOCKET) {
int error = WSAGetLastError();
Verbose::show("\n -- socket failed with error: " + toString<int>(error), always);
return false;
iResult = ::connect(socket_, ptr->ai_addr, (int)ptr->ai_addrlen);
if (iResult == SOCKET_ERROR) {
socket_ = INVALID_SOCKET;
int error = WSAGetLastError();
Verbose::show("WSAGetLastError returned " + toString(error));
continue;
break;
freeaddrinfo(result);
if (socket_ == INVALID_SOCKET) {
int error = WSAGetLastError();
Verbose::show("\n -- unable to connect to server, error = " + toString(error));
return false;
return true;
/////////Test stub////
int main()
title("Testing Socket Client", '=');
try
Verbose v(true);
SocketSystem ss;
SocketConnecter si;
while (!si.connect("localhost", 9080))
Verbose::show("client waiting to connect");
::Sleep(100);
title("Starting string test on client");
clientTestStringHandling(si);
title("Starting buffer test on client");
clientTestBufferHandling(si);
si.sendString("TEST_STOP");
Verbose::show("\n client calling send shutdown\n");
si.shutDownSend();
catch (std::exception& ex)
Verbose::show(" Exception caught:", true);//always = true
Verbose::show(std::string("\n ") + ex.what() + "\n\n");
I am trying to connect to the server, but the connector method shows the message "unable to connect to server" 
While debugging i found the iResult to be -1 which makes the socket INVALID_SOCKET
Kindly help resolve this

Answer 1

Hi askatral,
connect function can return invalid_socket for many reasons, what does the function WSAGetLastError return?
There are some Variables that I cannot find how it is declared, like "socket_" and "ptr". So I cannot check if there is anything wrong in your code.
Maybe this sample in the document of connect function is helpful for this issue:
https://msdn.microsoft.com/en-us/library/windows/desktop/ms737625(v=vs.85).aspx
Best regards,
Shu
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