WAVEOPENDESC

This structure contains information needed by a waveform input or waveform output device driver when devices are opened with a WODM_OPEN or WIDM_OPEN message.

typedef struct waveopendesc_tag {

HWAVE hWave;

LPWAVEFORMAT lpFormat;

DWORD dwCallback;

DWORD dwInstance;

} WAVEOPENDESC;

Fields

The WAVEOPENDESC structure has the following fields:

hWave

Specifies the client's handle to the device, assigned by MMSYSTEM. Use this handle when notifying the client with the DriverCallback function.

lpFormat

Specifies a far pointer to a WAVEFORMAT structure, indicating the waveform data format requested by the client.

dwCallback

Specifies either the address of a callback function, a window handle, or a task handle, depending on the flags specified in the dwParam2 parameter of the WODM_OPEN or WIDM_OPEN message. If this field contains a handle it is contained in the low-order word. The driver uses this information to notify the client using the DriverCallback function.

dwInstance

Specifies a DWORD of instance information for the client. This instance information is returned to the client whenever the driver notifies the client using the DriverCallback function.

See Also

WODM_OPEN, WIDM_OPEN