Windows MinGW-w64 (Qt6, C++20) Support & Standalone EXE Build Guide

[crazy-robotics]

Description

I am trying to build RViz2 on Windows using:

• Compiler: MinGW-w64 (GCC ≥ 11.2, C++20)
• GUI Framework: Qt6
• Goal: Generate a standalone .exe for distribution.

Currently, the official ROS 2 Windows support focuses on MSVC, and there is no clear documentation for MinGW-w64 builds. This makes it difficult for developers who prefer GCC-based toolchains on Windows.

Problem Details

1. Missing MinGW Build Support

   • Many ROS 2 packages assume MSVC and require patches for MinGW.
   • Example issues:
     • console_bridge fails with MinGW due to dllexport differences.
     • OGRE plugins need manual adjustments.

2. Qt6 Compatibility

   • The current CMakeLists.txt does not explicitly enforce Qt6 (defaults to Qt5 in some cases).

3. Standalone EXE Packaging

   • No official guide on bundling:
     • Qt6 .dll files (via windeployqt)
     • MinGW runtime dependencies
     • OGRE plugins

Requested Changes

1. Add MinGW Build Support

   • Provide MinGW-compatible patches for critical dependencies (console_bridge, rviz_ogre_vendor, etc.).
   • Document CMake flags for MinGW builds (-G "MinGW Makefiles").

2. Qt6 Modernization

   • Update CMakeLists.txt to explicitly support Qt6 (while maintaining Qt5 backward compatibility).

3. Standalone EXE Packaging Guide

   • Add a windows/README.md with steps to:
     • Use windeployqt for Qt dependencies.
     • Bundle MinGW runtime .dll files.
     • Handle OGRE plugin paths.

Example Workaround (Current Approach)

I managed to build RViz2 with MinGW by:

1. Manually patching console_bridge.
2. Forcing Qt6 in CMakeLists.txt:

   find_package(Qt6 REQUIRED COMPONENTS Core Gui Widgets OpenGL)  

3. Using windeployqt for .dll bundling.

However, this process is fragile and undocumented.

Additional Context

• Why MinGW?
  • Some developers prefer GCC toolchains for consistency with Linux.
  • MinGW builds may be smaller/faster than MSVC in some cases.
• Why Qt6?
  • Qt5 is nearing EOL (2023), and Qt6 offers better performance.

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Next Steps

1. Can the maintainers officially support MinGW-w64 builds?
2. Would a pull request (e.g., Qt6 modernization) be welcome?
3. Is there interest in adding a Windows packaging guide?

I’m happy to contribute patches/documentation if this is deemed useful!

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Labels (Suggested)

• enhancement
• windows
• build system
• documentation

[traversaro]

How did you installed the dependencies in this case? With mingw-w64 ?