pf wrote:
> Hi,
>
> I can implement a waveOutProc callback. But I can't understand how to
> incorporate into my class as it seems that the callback can't be a class
> member. When the callback fires I need to change variables in the class but
> can't access them as the callback isn't a member function.
>
> Some old MS code "CWaveOut.cpp" uses CreateSemaphore, ReleaseSemaphore etc.
> Is this the only way? Is this still supported in XP & Vista?
>
> Any help appreciated, thanks.
>
> Paul
>
>

The callback can't be a class member because the win API is C, and
cannot match C++ calling conventions. You can pass 'this' as the
instance parameter to waveOutOpen, and it will be passed to your
callback function. With that pointer you can call a member function.

But when you use a callback function there are a whole lot of things you
cannot do in it, as documented, because you are called in a system
thread context. Using a callback event or window message avoids that
set of restrictions. If you want to use the event you would use
CreateEvent and WaitForSingleObject.

--
Scott McPhillips [VC++ MVP]