How to OnMyEvent?

[Pascaluvr]

I am a self-taught FPC programmer under windows and have now started to learn the 'lazarus' way - and I'm very impressed.

In FPC I can use winproc to detect events other than those provided by default in Lazarus.  In windows its not unusual for external dll's to communicate with events via send/post message.

How can I get these into Lazarus?

Thanks in advance for any help