P2: Important In the source file "corelib/io/qwinoverlappedionotifier.cpp" line354 to 371 of version 5.6.0 Beta：
int t = msecs;
QElapsedTimer stopWatch;
stopWatch.start();
forever {
OVERLAPPED *triggeredOverlapped = waitForAnyNotified(t);
....
msecs = qt_subtract_from_timeout(msecs, stopWatch.elapsed());
....
}
It should be：
t = qt_subtract_from_timeout(msecs, stopWatch.elapsed());
It was introduced by the commit "ed0c0070f9b05c647019270dfc42073d071c830a"， and appeared to affect a lot of versions.