[libvirt] detection of events in kvm

Hello, I am student and doing a project in virtualization.My project requires detection of events in kvm like start of a virtual machine,shutoff of a virtual machine. So I want to know if there is any way by which I can detect these events.As in I want to write a code which will detect these events and then handle them.I am using ubuntu 13.04. I would be glad if anyone can help me. Thanks