Official documentation: doc:fcl/dbugintf
You can send debug output from your program to a debug server application. A debug server application is included with Lazarus; you can compile
and set it up as an external tool:
Alternatively, FPC has a text mode debug server which can also be used; see documentation.
To use it, add
dbugintf to the uses clause of the units you want to debug, then use SendDebug to send messages to the debug server.
For more details, please see the documentation.
--DD 05:38, 3 October 2015 (CEST): Does not seem to be thread safe!