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MIDIOPENDESC structure (mmddk.h)

  • Article

The MIDIOPENDESC structure is a client-filled structure that provides information about how to open a MIDI device.

Syntax

typedef struct midiopendesc_tag {
  HMIDI          hMidi;
  DWORD_PTR      dwCallback;
  DWORD_PTR      dwInstance;
  DWORD_PTR      dnDevNode;
  DWORD          cIds;
  MIDIOPENSTRMID rgIds[1];
} MIDIOPENDESC;

Members

hMidi

Specifies the handle that the client uses to reference the device. This handle is assigned by WINMM. Use this handle when you notify the client with the DriverCallback function.

dwCallback

Specifies either the address of a callback function, a window handle, or a task handle, depending on the flags that are specified in the dwParam2 parameter of the MODM_OPEN message. If this field contains a handle, it is contained in the low-order word.

dwInstance

Specifies a pointer to a DWORD that contains instance information for the client. This instance information is returned to the client whenever the driver notifies the client by using the DriverCallback function.

dnDevNode

Specifies a device node for the MIDI output device, if it is a Plug and Play (PnP) MIDI device.

cIds

Specifies the number of stream identifiers, if a stream is open.

rgIds[1]

Specifies an array of device identifiers. The number of identifiers is given by the cIds member.

Requirements

Requirement Value
Minimum supported client Available in Windows XP and later Windows operating systems.
Header mmddk.h (include Mmddk.h, Mmsystem.h, Windows.h)

See also

DriverCallback