We use Mingw for cross-compilation of Windows versions on Linux. It is currently used both in the tests and for the Windows release binaries.
MSYS2 is a way to build the project on Windows. It currently offers gcc at versions 7 or higher.
MSYS also provides clang. We don’t currently support using clang here, but work to that end is welcome.
Our goal with compiler support is to make it as easy as possible for new contributors to get started with development of the game, while also using the newest compilers (and thus language standards) that we can.
To that end, we aim to support gcc and clang up to the newest stable versions and back to those shipping in any supported version of a popular distribution or relevant development environment, including Ubuntu, Debian, MSYS, and XCode.
Since macOS can be harder to update we have active developers and users on unsupported versions of macOS we would like to support. To support a reasonable number of users we aim to support at least 95% of users by macOS market share.
At the time of writing:
- Bionic is about to end general support, so we aim to support the next oldest Ubuntu LTS (Focal). Focal defaults to g++ 9.3 and clang 10.
- Debian stable is Bullseye, and defaults to g++ 10.2.
- Oldest supported Fedora is 36, which uses gcc 12.0.
- MSYS offers gcc 12.2.
- macOS 10.13+ has 96.0% market share and that corresponds to XCode 10.1.
In practice, compiler support is often determined by what is covered in our automated testing.
At time of writing, the oldest relevant compiler is XCode 10.1, the latest supported on macOS 10.13, which is based on LLVM 6.
With gcc 9.3, clang 10, and XCode 10.1 we can get all the C++17 language features and most but not all of the C++17 library features. The following C++17 features are not supported widely enough for us to use:
- Parallel algorithms and execution policies.
- Hardware interference size.
- File system library (note, we already have a backported version of the filesystem library bundled with CDDA, so that can be used instead).
- Polymorphic memory resources.
- Mathematical special functions.
- Elementary string conversions for floating point.
- Array support in
Some of these are not even supported in the latest XCode so we cannot expect to use them for many years.
The limiting factor preventing us from using newer C++ features is primarily XCode, where we would probably want version 13 before moving to C++20.
To monitor macOS market share we have a helper script in tools/macos-market-share.py. Download the CSV-formatted data from statcounter and process it with that script to get a summary of cumulative market share as it varies across time. For example, this output:
2021-05 :: 10.11: 8.2 10.12: 11.0 10.13: 18.3 10.14: 27.0 10.15: 98.1 2021-06 :: 10.11: 6.6 10.12: 9.3 10.13: 16.3 10.14: 24.6 10.15: 99.0 2021-07 :: 10.11: 4.7 10.12: 7.4 10.13: 14.2 10.14: 22.1 10.15: 99.3
shows that cumulative market share for versions up to 10.11 first dropped below 5% in 2021-07, at which point we (following the above guidelines) allowed ourselves to drop support for 10.11.