winmm WAVE_MAPPER patch

[Eric Pouech]

> Wine on the other hand doesn't return an error when there are no
> devices.  I haven't looked at the data it returns but it must be
> uninitialized garbage because there is no device to return the
> capabilities of.
not exactly. The wave mapper itself (dlls/winmm/wavemap/wavemap.c, 
function wodGetCaps) does return something.

> After stepping through the code, the line that I changed is the line
> that should have returned the error but didn't.   The existing code
> basically is:  if the requested device is the default device and the
> default device is not set to a valid device, return an error.  
it's not the default device, it's the mapper. It's up to the mapper to 
actually pick up what is supposed to be the default device.
The existing code does (lolvldrv.c, in MMDRV_GetById):
- in the current class of device (in your case wave out), if the ID is 
the one of the mapper, and a mapper exists for the class, then use the 
device of the mapper as the real device

That's why I suggested that wavemap is more likely to be fixed rather 
than winmm itself. I do think that what windows do for 
waveOutGetDevCaps(-1...) is:
- in winmm, get -1 as the mapper and pass the WODM_GETDEVCAPS to the 
mapper driver
- in wavemap, while handling WODM_GETDEVCAPS, pass the message to the 
default device
This last part is broken right now (from what you report). It should 
then pass the WODM_GETDEVCAPS to the actual default device (it already 
does it if first waveOutGetDevCaps is called with a handle and not a 
device ID), instead of returning values for the mapper (which is not 
very sensible).

A+