question about snmp trap receiver implementation

Dear all
	
	Now I am developping a deamon that could receive snmp trap message. I 've learned snmptrapd program, but I couldn't get raw trap mesage clearly.."snmptrapd" use function "snmp_read" do almost everything(read packet, parse packet , print packet), I could'nt have the chance to get raw snmp trap message and parse it freely.

	so who can help me using net-snmp library to get the snmp trap message and parse it free?	
	
	Thanks a lot~

Best regards            
Anders