@KroMignon said in QTcpSocket state always connected:
result = setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &enableKeepAlive, sizeof(enableKeepAlive));
result = setsockopt(fd, IPPROTO_TCP, TCP_KEEPIDLE, &maxIdle, sizeof(maxIdle));
result = setsockopt(fd, IPPROTO_TCP, TCP_KEEPCNT, &count, sizeof(count));
result = setsockopt(fd, IPPROTO_TCP, TCP_KEEPINTVL, &interval, sizeof(interval));
TCP_KEEPIDLE / TCP_KEEPCNT / TCP_KEEPINTVL - linux options, aren't they?
So for windows I found next solution:
add this lib to your project *.pro file
LIBS += -lws2_32
Next after socket connection you should use:
#include <Ws2tcpip.h>
//------
// socket is QTcpSocket*
if (socket->state() == QAbstractSocket::ConnectedState) {
int fd = socket->socketDescriptor();
DWORD dwBytesRet = 0;
struct tcp_keepalive alive; // your options for "keepalive" mode
alive.onoff = TRUE; // turn it on
alive.keepalivetime = 30000; // delay (ms) between requests, here is 30s, default is 2h (7200000)
alive.keepaliveinterval = 5000; // delay between "emergency" ping requests, their number (6) is not configurable
/* So with this config socket will send keepalive requests every 30 seconds after last data transaction when everything is ok.
If there is no reply (wire plugged out) it'll send 6 requests with 5s delay between them and then close.
As a result we will get disconnect after approximately 1 min timeout.
*/
if (WSAIoctl(fd, SIO_KEEPALIVE_VALS, &alive, sizeof(alive), NULL, 0, &dwBytesRet, NULL, NULL) == SOCKET_ERROR) {
QDebug() << "WSAIotcl(SIO_KEEPALIVE_VALS) failed with err#" << WSAGetLastError();
return;
}
}
