[Bug 19523] winmm: Multiple waveOutOpen calls on single device supported by Windows, not Wine

[Eric Pouech]

>> let's take the wave out driver interface as example:
>>
>> DWORD WINAPI wodMessage(UINT wDevID, UINT wMsg, DWORD_PTR dwUser,
>>                        DWORD_PTR dwParam1, DWORD_PTR dwParam2);
>>
>> in case wMsg in WODM_OPEN, dwUser is expected to be a pointer to a 
>> DWORD, that
>> the driver is supposed to filled with a unique instance ID (to 
>> identify the
>> stream)
>>
>> in other (subsequent) messages, winmm passes in dwUser the unique ID 
>> defined by
>> the driver at WODM_OPEN time
>>
>> winmm correctly supports this scheme (see MMDRV_Open in 
>> dlls/winmm/lolvldrv.c)
>
> No offense, but looking at MMDRV_Open, it's clear as mud to me that 
> dwDriverInstance has this meaning and corresponds to dwUser.  Is there 
> any documentation of the low-level driver interface?
google for "Windows NT DDK - Multimedia Drivers.pdf"
or http://www.osronline.com/ddkx/w98ddk/mmedia_4otx.htm
from the later

DWORD /dwUser/
    For the *WODM_OPEN* message, the driver should fill this location
    with its instance data. For any other messages, the instance data is
    returned to the driver. Drivers supporting multiple clients can use
    this instance data to keep track of which client is associated with
    the message. 

the former has way more details on the message processing though
>
>
>> but, none of the wine drivers correctly initialize the dwUser while 
>> processing
>> the various XXXX_OPEN messages
>
> Does that mean this functionality is untested?
>
IIRC I tested it a century ago with the native wave mapper (for 16 and 
32 versions of it)
A+

-- 
Eric Pouech
"The problem with designing something completely foolproof is to underestimate the ingenuity of a complete idiot." (Douglas Adams)