Hi,
I need some information about threads and callbacks. I already found out that: - SetEvent delivers "asynchronously" and can unblock threads WaitingForMultipleObjects. No callback is involved (which does not mean that the current thread cannot be preempted by another one awakening). Therefore, this seems strange: LeaveCriticalSection(&wma->cs); SetEvent(wma->hStopEvent); EnterCriticalSection(&wma->cs); I mean, if you left it, anything can have happened in between (including close of the device).
- Likewise, notifications (to either thread or window) deliver asynchronously as well, to a message queue. No callback is involved.
- OTOH functions like waveOutReset will callback into the applications (via Un-/PrepareBuffer etc.). In this example, LeaveCriticalSecion seems necessary, because waveOutReset does everything on the caller's thread, which might cause a driver to be entered recursively. LeaveCriticalSection(&wma->cs); dwRet = waveOutReset(wma->hWave); EnterCriticalSection(&wma->cs); HOWEVER, Critical sections can be re-entered by the same thread. They are no inner-thread protection. Why then leave it? Is the Critical section adequate at all? What else is useable?
Is it allowed for an application to call waveOpen in one thread and then call waveOut, waveStart, waveAddBuffer etc. from another one?
Is it allowed to mmioSeek/mmioRead from different threads using the same handle?
Thanks for your help, Jörg Höhle