Gui debugger freezing and windows 10

Hi, I am trying to adapt some code I wrote maybe 10 years ago using a few xpce dialogs. Operating system Win XP sp3, swi-prolog version 6.6.4. The gui debugger/tracer works as expected in that environment, even with my simple dialogs. Now I want to revive this code for windows 10 and maybe linux with the latest swi-prolog. However there seems to be something fundamental about the debugger that I don’t understand:
Each time I want to jump over these few dialogs everything freezes and I have to stop swi-prolog using the task manager. I tried in windows 7 with similar result. Any idea what I might be doing wrong?

I made a simple test with the gui-debugger. Loaded the source code for “constraint-demo” in the xpce examples that comes with Swi-prolog, put “gtrace” in the code and executed the predicate. With version 6.6.4 (32-bit, win XP) the gui tracer works as expected. With version 8.2.4 (64-bit, win 10) the gui-tracer hangs. Maybe this is a 32-bit versus 64-bit problem? I searched the forum and did not find any clue. Will test with latest 32-bit version under win 10 and report again.

Hangs with 32-bit version too unfortunately. Should I file a bug?

One more test: gtrace of “constraint_test” works for me under linux 64-bit. Swi-prolog version 8…2…2.

Seems you are trying to trace xpce programs. Running xpce programs is a bit harder since xpce by default runs in a thread (pce). This allows using the development tools while your query is running. For what you seem to be doing it may make sense to call

?- set_prolog_flag(xpce_threaded, false).

Make sure to set this before making any xpce call or even load the library. You can verify this flag did is work by running

?- threads.

and verify pce is not listed.

As the thread model for Windows and Linux wrt graphics handling is quite different the impact of using xpce with multiple threads varies. As a rule of thumb, do not use xpce from multiple threads. To some extend it works, but it deadlocks easily. There are no plans to fix that.