Here's an example:
https://github.com/MesserLab/SLiM/actions/runs/25653704791
The error, for both builds, looks like:
Linking CXX executable slim.exe
D:/a/_temp/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/16.1.0/../../../../x86_64-w64-mingw32/bin/ld.exe: CMakeFiles/slim.dir/objects.a(main.cpp.obj):main.cpp:(.text.startup+0x595): undefined reference to `std::basic_filebuf<char, std::char_traits >::_close()'
collect2.exe: error: ld returned 1 exit status
So it's a link-time error, not a compile-time error. There are no calls to close() in main.cpp for slim, I don't think. There are two calls to fclose(), but the same two calls to fclose() also occur for main.cpp for eidostool, and that built and linked successfully, as can be seen a bit higher in the logs. So maybe those fclose() calls are just a red herring; or maybe something about the way main.cpp for eidostool does things is subtly different, such that the error is not triggered.
Since it emerged spontaneously (I don't think I was working on SLiM at all at the time, it failed in the weekly test build), my guess is that GitHub changed something in their build environment for Windows. Beyond that I have no idea. Maybe someone here with Windows knowledge can figure it out?
Here's an example:
https://github.com/MesserLab/SLiM/actions/runs/25653704791
The error, for both builds, looks like:
So it's a link-time error, not a compile-time error. There are no calls to close() in main.cpp for
slim, I don't think. There are two calls to fclose(), but the same two calls to fclose() also occur for main.cpp foreidostool, and that built and linked successfully, as can be seen a bit higher in the logs. So maybe those fclose() calls are just a red herring; or maybe something about the way main.cpp foreidostooldoes things is subtly different, such that the error is not triggered.Since it emerged spontaneously (I don't think I was working on SLiM at all at the time, it failed in the weekly test build), my guess is that GitHub changed something in their build environment for Windows. Beyond that I have no idea. Maybe someone here with Windows knowledge can figure it out?