Allow QWinEventNotifier to coexist with waiting functions

Many subclasses of QIODevice have a functionality to block execution
until some asynchronous I/O operation completes. In case we are using
QWinEventNotifier, a typical reimplemented waitFor{ReadyRead
|BytesWritten}() function could look like:

  if (WaitForSingleObject(notifier.handle(),...) == WAIT_OBJECT_0) {
      notifier.setEnabled(false);
      ResetEvent(notifier.handle());

      bool res = GetOverlappedResult(...);
      ...
      return true;
  }

Despite the fact that the operation ends synchronously, it leaves the
notifier in a state that indicates it has received the event, so its
next call to setEnabled(true) will produce a fake notification.

So, we should reset a notifier's history before enabling it again.

Change-Id: I62a9dd809ce6a7a40e9d8038f2a49299b36f8142
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

0 files changed, 0 insertions, 0 deletions