ArcChat

ArcChat is a small Qt 6 C++ and QML starter app.

The C++ side only owns process startup and the QML engine. The UI is a Qt Quick Controls ApplicationWindow, registered through qt_add_qml_module and started with QQmlApplicationEngine::loadFromModule("ArcChat", "Main"). That keeps the QML in Qt's module/resource/qmlcache pipeline instead of loading a loose QML file by URL.

Requirements

• Qt 6.10 with Qt Quick, QML, and Quick Controls 2
• CMake 3.30 or newer
• Ninja for the provided presets
• sccache for the compiler cache used by the presets
• Clang (the Windows preset uses the MinGW-style clang/clang++, not clang-cl)

On Windows the toolchain is MSYS2 UCRT64. Install everything with pacman:

pacman -S --needed \
  mingw-w64-ucrt-x86_64-cmake \
  mingw-w64-ucrt-x86_64-ninja \
  mingw-w64-ucrt-x86_64-sccache \
  mingw-w64-ucrt-x86_64-clang \
  mingw-w64-ucrt-x86_64-clang-tools-extra \
  mingw-w64-ucrt-x86_64-lld \
  mingw-w64-ucrt-x86_64-qt6-base \
  mingw-w64-ucrt-x86_64-qt6-declarative \
  mingw-w64-ucrt-x86_64-qt6-languageserver \
  mingw-w64-ucrt-x86_64-qt6-doc

When the build is driven by the MSYS2 UCRT64 cmake, Qt is discovered automatically from the UCRT64 prefix, so no Qt6_DIR/QT_DIR is needed. If you use a different CMake, point it at the Qt CMake package directory:

$env:Qt6_DIR = "C:\msys64\ucrt64\lib\cmake\Qt6"

Build

Windows (with C:\msys64\ucrt64\bin on PATH):

cmake --preset windows-debug
cmake --build --preset windows-debug
.\build\debug\bin\ArcChat.exe

Linux:

cmake --preset linux-debug
cmake --build --preset linux-debug
./build/debug/bin/ArcChat

macOS:

cmake --preset macos-debug
cmake --build --preset macos-debug
open build/macos-debug/bin/ArcChat.app

The configure step syncs compile_commands.json to build/compile_commands.json so clangd, clang-format, and clang-tidy can use the same database.

VS Code QML Language Server

The workspace settings pass build/debug to qmlls and disable qmlls-triggered CMake rebuilds. Run the configure/build commands once, then use Qt: Restart QML Language Server if completions do not appear immediately after opening the folder.