WIDM_LOWPRIORITY

The WIDM_LOWPRIORITY message requests a waveform input driver to run at low priority.

Parameters

uDeviceId

Device identifier (0, 1, 2, and so on) for the target device.

uMsg

WIDM_LOWPRIORITY

dwUser

Device instance identifier.

dwParam1

Not used.

dwParam2

Not used.

Return Value

The driver should return MMSYSERR_NOERROR if the operation succeeds. Otherwise it should return one of the MMSYSERR or WAVERR error codes defined in mmsystem.h.

Comments

A client sends the WIDM_LOWPRIORITY message by calling the user-mode driver’s widMessage entry point, passing the specified parameters.

Typically, the user-mode driver calls DeviceIoControl to send the kernel-mode driver an IOCTL_WAVE_SET_LOW_PRIORITY control code. Kernel-mode drivers using soundlib.lib allow only one client to be running at low priority.

Support for this message by user-mode drivers is optional.