If there is no response to a communication request within the time-out period specified for a destination entity, and if retransmissions are specified for the entity, the Microsoft WinSNMP implementation retransmits the request. A call to the SnmpCancelMsg function can cancel this retransmission cycle and release internal data structures associated with the message request.
Note that it is possible for a destination entity to receive an SNMP message that has been canceled by a call to the SnmpCancelMsg function. It is also possible that a destination entity can respond to a canceled SNMP message. This is because transaction queuing occurs at multiple levels. However, once a message has been canceled by a call to SnmpCancelMsg, the Microsoft WinSNMP implementation will not retransmit the message, submit a response PDU, or send a time-out notification to the application for that message.