How to catch GUID_IO_MEDIA_EJECT_REQUEST device event

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Win32

API

I'm developing an application in which I need to catch GUID_IO_MEDIA_EJECT_REQUEST device event. I have searched a lot on internet but could not detailed information about this device event.
I have done following steps:
1)Registered device for notification through RegisterDeviceNotification().
2)On WM_DEVICECHANGE, in DBT_CUSTOMEVENT checking if device type is handle or not.
3)If it is handle then getting eventguid from lParam & comparing with GUID_IO_MEDIA_EJECT_REQUEST.

But I'm not getting GUID_IO_MEDIA_EJECT_REQUEST GUID.
Is there any step missing?