On Aug 29 16:17, Corinna Vinschen wrote: > On Aug 29 14:39, Jon TURNEY wrote: > > On 08/08/2010 12:04, Andy Koppe wrote: > > >On 7 August 2010 23:07, Jon TURNEY wrote: > > >>Hmmm, looking again at the implementation of select(), I don't immediately > > >>see that when waiting on /dev/windows, it checks that the message queue > > >>has > > >>old messages on it before waiting. The MSDN documentation for > > >>MsgWaitForMultipleObjects() seems to says that messages which had arrived > > >>before the last PeekMessage() etc. aren't considered new and so don't end > > >>the wait? > > >[...] > > Thanks for the testcase. I examined this and I think I have a > workaround. MSDN states that there's a flag QS_ALLPOSTMESSAGE for > MsgWaitForMultipleObjects, which is not cleared by PeekMessage, if the > wMsgFilterMin and wMsgFilterMax arguments are not both 0. So, what I > did was to add the QS_ALLPOSTMESSAGE flag to the > MsgWaitForMultipleObjects call in select.cc, and to change the > PeekMessage call in select.cc:peek_windows() from > > PeekMessage (&m, (HWND) h, 0, 0, PM_NOREMOVE) > > to > > PeekMessage (&m, (HWND) h, 1, UINT_MAX, PM_NOREMOVE) > > Same in your above test application. This appears to do the trick. > However, I'm not exactly sure if that's a valid fix. Patch below.
Hmm, this ignores the potential WM_NULL message, afaics. For some reason, using PeekMessage (&m, (HWND) h, 0, UINT_MAX, PM_NOREMOVE) results in MsgWaitForMultipleObjects hanging, too. OTOH, using PeekMessage (&m, (HWND) h, 0, 16, PM_NOREMOVE) && PeekMessage (&m, (HWND) h, 17, UINT_MAX, PM_NOREMOVE) does not. Go figure. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
