Bug or wrong usage globals?

[Artem535]

Hi! At the moment, I'm working on a personal project with Slint and C++20. I have some problems with globals. In the project, I’m trying to split the app into pages and widgets. Here’s what the project structure looks like:

|── CMakeLists.txt
...
├── src
│   ├── app
│   │   ├── app.cppm
│   │   └── CMakeLists.txt
│   ├── config
│   │   ├── CMakeLists.txt
│   │   ├── config.cppm
│   │   └── rfl_path.cppm
│   ├── database
│   │   ├── CMakeLists.txt
│   │   ...
│   │   └── slint_adapter.cppm
│   ├── main.cpp
│   └── widgets
│       ├── calendar_widget_logic.cppm
│       └── CMakeLists.txt
...
└── ui
    ├── app
    │   └── mainwindow.slint
    ├── pages
    │   └── client_info.slint
    └── widgets
        └── calendar.slint

I defined two globals in different files (calendar.slint and client_info.slint) and tried to export them in my mainwindow.slint. It works when I export only one global, so I can use it on the C++ side, but when I try to use both, I get a segmentation fault when accessing them from C++ (even though the code compiles without errors).

I tried to debug this, but I found that:

So, I have a few questions:

• Is it possible to use two globals?
• Is it okay to use export in order to access these globals from the C++ side?
• Am I correct in understanding that I can’t access a global unless I use it in the main window?

[ogoffart]

Two globals shouldn't be a problem.

Maybe there is a bug in Slint.

Would you be able to share your code so i can try to reproduce?

[Artem535]

Yes, the full code is here. I also tried to create a minimal example with this problem using the slint C++ template, but the project could not be linked due to this error.

/usr/bin/ld: CMakeFiles/my_application.dir/slint_generated_global_2_1.cpp.o: in function `Global_2::Global_2(SharedGlobals const*)':
slint_generated_global_2_1.cpp:(.text+0x0): multiple definition of `Global_2::Global_2(SharedGlobals const*)'; CMakeFiles/my_application.dir/slint_generated_app-window_1.cpp.o:slint_generated_app-window_1.cpp:(.text+0xc80): first defined here
/usr/bin/ld: CMakeFiles/my_application.dir/slint_generated_global_2_1.cpp.o: in function `Global_2::invoke_callback_2() const':
slint_generated_global_2_1.cpp:(.text+0x30): multiple definition of `Global_2::invoke_callback_2() const'; CMakeFiles/my_application.dir/slint_generated_app-window_1.cpp.o:slint_generated_app-window_1.cpp:(.text+0xcb0): first defined here
/usr/bin/ld: CMakeFiles/my_application.dir/slint_generated_global_2_1.cpp.o: in function `Global_2::Global_2(SharedGlobals const*)':
slint_generated_global_2_1.cpp:(.text+0x0): multiple definition of `Global_2::Global_2(SharedGlobals const*)'; CMakeFiles/my_application.dir/slint_generated_app-window_1.cpp.o:slint_generated_app-window_1.cpp:(.text+0xc80): first defined here

[Artem535]

Hi! Any news on that? Maybe I should provide more information?

[ogoffart]

Sorry, i haven't had time to look at it yet.

[Artem535]

Hi, I tried playing around with the minimal example and found some interesting things, I think. I created two experiments: one where all globals were defined in the main file (in the project, this is app-window.slint), and another where they were defined in a separate file (in the project, this is all_globals.slint). The first experiment compiled without any problems, and all globals worked fine. However, in the second experiment, I encountered an issue. I simply couldn't compile the program. Here's the log from the compilation:

-- Configuring done (0.0s)
-- Generating done (0.0s)
-- Build files have been written to: /home/artem/Projects/C++/minimal_example/build
CMakeFiles/my_application.dir/build.make:88: warning: overriding recipe for target 'slint_generated_app-window_1.cpp'
CMakeFiles/my_application.dir/build.make:79: warning: ignoring old recipe for target 'slint_generated_app-window_1.cpp'
[ 16%] Generating app-window.h
CMakeFiles/my_application.dir/build.make:88: warning: overriding recipe for target 'slint_generated_app-window_1.cpp'
CMakeFiles/my_application.dir/build.make:79: warning: ignoring old recipe for target 'slint_generated_app-window_1.cpp'
[ 33%] Building CXX object CMakeFiles/my_application.dir/src/main.cpp.o
[ 50%] Building CXX object CMakeFiles/my_application.dir/slint_generated_app-window_1.cpp.o
[ 66%] Linking CXX executable my_application
/usr/bin/ld: CMakeFiles/my_application.dir/slint_generated_all_globals_1.cpp.o: in function `Global_2::Global_2(SharedGlobals const*)':
slint_generated_all_globals_1.cpp:(.text+0x0): multiple definition of `Global_2::Global_2(SharedGlobals const*)'; CMakeFiles/my_application.dir/slint_generated_app-window_1.cpp.o:slint_generated_app-window_1.cpp:(.text+0xc90): first defined here
/usr/bin/ld: CMakeFiles/my_application.dir/slint_generated_all_globals_1.cpp.o: in function `Global_2::invoke_callback_2() const':
slint_generated_all_globals_1.cpp:(.text+0x30): multiple definition of `Global_2::invoke_callback_2() const'; CMakeFiles/my_application.dir/slint_generated_app-window_1.cpp.o:slint_generated_app-window_1.cpp:(.text+0xcc0): first defined here
/usr/bin/ld: CMakeFiles/my_application.dir/slint_generated_all_globals_1.cpp.o: in function `Global_2::Global_2(SharedGlobals const*)':
slint_generated_all_globals_1.cpp:(.text+0x0): multiple definition of `Global_2::Global_2(SharedGlobals const*)'; CMakeFiles/my_application.dir/slint_generated_app-window_1.cpp.o:slint_generated_app-window_1.cpp:(.text+0xc90): first defined here
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [CMakeFiles/my_application.dir/build.make:151: my_application] Error 1
make[1]: *** [CMakeFiles/Makefile2:83: CMakeFiles/my_application.dir/all] Error 2
make: *** [Makefile:91: all] Error 2

I'm also attaching the build.make.zip and
generatted.zip files to this message. Can you please check if you have time for this?