The WIDM_GETDEVCAPS message requests a waveform input driver to return the capabilities of a specified device.
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. See waveInGetDevCaps return values in the Win32 SDK.
A client sends the WIDM_GETDEVCAPS 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_GET_CAPABILITIES control code.
The user-mode driver fills the WAVEINCAPS structure.