MODM_GETNUMDEVS - NtDoc
Native API online documentation, based on the System Informer
(formerly Process Hacker) phnt
headers
// mmddk.h
DWORD modMessage(
UINT uDeviceID,
UINT uMsg,
DWORD_PTR dwUser,
DWORD_PTR dwParam1,
DWORD_PTR dwParam2
);
View the official Windows hardware development documentationNo description available.
WINMM sends the MODM_GETNUMDEVS message to the modMessage function of a MIDI output driver to request the number of MIDI output devices available.
uDeviceID Specifies the ID of the target device. Device IDs are sequential and have an initial value of zero and a final value that is equal to one less than the number of devices that the driver supports.
uMsg WINMM sets this parameter to MODM_GETNUMDEVS when it calls modMessage to process this message.
dwUser Use this parameter to return instance data to the driver. Drivers that support multiple clients can use this instance data to keep track of the client that is associated with the message.
dwParam1 Not used.
dwParam2 Not used.
The modMessage function returns the number of MIDI output devices that the driver supports.
Drivers can be structured in several ways. The simplest and most common drivers use one physical device to support one logical device. Drivers can also support multiple logical devices by using a single physical device. For example, a driver can use a single digital signal processor (DSP) to support two different types of internal synthesizers. Such a driver would return a value of "2" in response to the MODM_GETNUMDEVS message.
| Target platform | Desktop |
| Version | Available in Windows XP and later Windows operating systems. |
| Header | Mmddk.h (include Mmddk.h, Mmsystem.h, or Windows.h) |