================================================================ Logtalk - Open source object-oriented logic programming language Release 2.30.2 Copyright (c) 1998-2007 Paulo Moura. All Rights Reserved. ================================================================ To load all entities in this group load the debugging_loader.lgt utility file: | ?- logtalk_load(debugging_loader). You will need to load FIRST the events_loader.lgt file otherwise you will get a runtime error. The object event_dbg enables you to: - spy all or specific messages to an object - trace an execution - specify the streams used for debugger input/output These capabilities rely on the use of the event-based programming built in Logtalk. That means that you can only debug public messages sent using the ::/2 operator. You can have any number of debuggers active simultaneously, possibly assigning different input/output streams to each one. Input/output is one area where Prologs compilers can differ, sometimes because of differences in the underlying operating system. Therefore, it is advisable that you look at the code of class debugger before trying to use it. The i/o operations are done by the methods output/3, query_user/1 and execute_option/1.