Hi,

I'm currently debugging my multi monitor code for Eagle and every time I shut down Eagle after creating a EagleGraphicsContext( a window ) it hangs in Allegro5WindowManager::Destroy here :
https://github.com/EdgarReynaldo/EagleGUI/blob/master/src/backends/Allegro5/Allegro5WindowManager.cpp#L304-L314

The Allegro5WindowManager process is alive and waiting on an event (in this case, EAGLE_EVENT_WM_DESTROY :
https://github.com/EdgarReynaldo/EagleGUI/blob/master/src/backends/Allegro5/Allegro5WindowManager.cpp#L37

which should have been sent by the above code, but that message never arrives. Can anyone help me debug this and figure out why my event is missing?

Edgar

ALLEGRO_EVENT_QUEUE and ALLEGRO_EVENT_SOURCE are both completely separate from an ALLEGRO_DISPLAY.

I don't know what's wrong. If I set a breakpoint in WM::Destroy I see the event get emitted! It is just never received by the A5WindowManagerProcess. I only unregister the event source once, on destruction later on in WM::Destroy here :
https://github.com/EdgarReynaldo/EagleGUI/blob/master/src/backends/Allegro5/Allegro5WindowManager.cpp#L316-L321

I create and initialize and register them here :
https://github.com/EdgarReynaldo/EagleGUI/blob/master/src/backends/Allegro5/Allegro5WindowManager.cpp#L264-L277

Those are the only places I create or destroy or register or unregister the window_event_source. This is everything grep returns that has anything to do with the window event source :

c:\ctwoplus\progcode\Eagle5GUI_GIT_BitBucket\src>grep -r -E -I -n "window_event_source" .*.*
.\backends/Allegro5/Allegro5WindowManager.cpp:42:      if (ev.any.source == &(a5man->window_event_source)) {
.\backends/Allegro5/Allegro5WindowManager.cpp:130:   ev.any.source = &window_event_source;
.\backends/Allegro5/Allegro5WindowManager.cpp:133:   al_emit_user_event(&window_event_source , &ev , 0);
.\backends/Allegro5/Allegro5WindowManager.cpp:150:   if (ev.any.source == &window_event_source) {
.\backends/Allegro5/Allegro5WindowManager.cpp:245:      window_event_source(),
.\backends/Allegro5/Allegro5WindowManager.cpp:264:   al_init_user_event_source(&window_event_source);
.\backends/Allegro5/Allegro5WindowManager.cpp:277:   al_register_event_source(window_queue , &window_event_source);
.\backends/Allegro5/Allegro5WindowManager.cpp:307:      ev.any.source = &window_event_source;
.\backends/Allegro5/Allegro5WindowManager.cpp:311:      al_emit_user_event(&window_event_source , &ev , 0);
.\backends/Allegro5/Allegro5WindowManager.cpp:317:      al_unregister_event_source(window_queue , &window_event_source);
.\backends/Allegro5/Allegro5WindowManager.cpp:318:      al_destroy_user_event_source(&window_event_source);

c:\ctwoplus\progcode\Eagle5GUI_GIT_BitBucket\src>

Tested on Windows and Linux, that's all I have access to. Does the exact same thing, whether in Windows 10, or OpenSUSE 44.

It currently builds with C::B and MinGW/GCC and needs allegro installed either in the root directory in a folder called allegro or in usr/local/lib, or in your compiler directory (eww).

This is probably paranoid, but I suspect it's a heisenbug or memory corruption or something. I tried to rule out race conditions by creating a EagleLogGuard, which seems to be working fine to serialize log output.

EDIT
There is some hanky panky going on in my code somewhere....

If I add in this line :

https://github.com/EdgarReynaldo/EagleGUI/blob/master/src/backends/Allegro5/Allegro5WindowManager.cpp#L38

   EAGLE_ASSERT(al_is_event_source_registered(window_queue , &(a5man->window_event_source)));

It passes the assert when closing the window, but then immediately fails the assert. Something is "un-registering" my window_event_source from the window queue.

There's also something fishy here in my log :

EAGLE INFO     : Allegro5WindowManager::AddDisplay - adding ALLEGRO_DISPLAY* 0420c2e0 .
...
EAGLE INFO     : A5WindowManagerProcess : Closing display 0420a0b0

I only ever created one display! Why is their address different?

I found the issue.

Super facepalm here.

Look at the highlighted lines :
https://github.com/EdgarReynaldo/EagleGUI/blob/master/src/backends/Allegro5/Allegro5WindowManager.cpp#L56-L66

The event I was sending for EAGLE_EVENT_WM_CLOSE_WINDOW was a user event not a display event, but I was accessing ev.display.source, which was garbage (or in this case happened to be the same as &window_event_source, which un-registered it from the queue and prevented the EAGLE_EVENT_WM_DESTROY message to be received. This has taken me weeks to find.

Glad you got it figured out!