Cross Platform Hello

Simple C++ “Hello World” that builds on Linux, macOS, and Windows using CMake. The repository also ships a GitHub Actions workflow that runs native compilers on each platform, publishes the resulting binaries as artifacts, and automatically creates GitHub Releases when you push a tag.

Build locally

1. Configure the project (CMake 3.15+ is enough):

   cmake -S . -B build -DCMAKE_BUILD_TYPE=Release

2. Build and (optionally) install:

   cmake --build build --config Release
   cmake --install build --config Release --prefix dist

   The executable ends up in build/cross_platform_hello on single-config generators (Linux/macOS) or build/Release/cross_platform_hello.exe on multi-config ones such as MSVC.

On macOS you can run everything above with a single helper script (it still uses the locally installed Apple toolchain). Before running it, make sure the Xcode Command Line Tools are installed so that xcrun and the macOS SDK headers are available (xcode-select --install installs them on stock systems).

./build_macos.sh

Build via Docker (no local toolchain)

If you would rather not install any native build tools, use the provided container workflow. It produces Linux binaries natively and Windows binaries via MinGW cross compilation.

./docker-build.sh

or on Windows:

docker-build.bat

Both scripts build the cross-platform-hello-builder image (based on Fedora 40) and run scripts/build-all.sh inside it. Results are written to dist/linux and dist/windows. Generating macOS binaries still requires macOS tooling, so those builds are produced by GitHub-hosted runners only.

Windows outputs are statically linked with the MinGW runtimes, so dist/windows/bin/cross_platform_hello.exe runs standalone on a vanilla Windows installation.

Continuous integration

The workflow in .github/workflows/ci.yml runs on ubuntu-latest, macos-latest, and windows-latest. Each matrix job:

• Uses the native compiler (g++/clang++ on Linux/macOS, MSVC on Windows)
• Configures and builds the project with CMake
• Installs the executable into a small dist directory
• Uploads the directory as a build artifact

When you push a tag that starts with v (for example v1.0.0), the workflow bundles the artifacts from every platform, creates a GitHub Release, and attaches the bundled binaries. Pushing to the main branch (or opening pull requests) still runs the build matrix but skips the release step.

ℹ️ MinGW cannot build macOS binaries. macOS builds are only produced by the macOS runner, which has access to Apple toolchains.

Cutting a release

1. Update the code as needed and commit the changes.
2. Create and push a tag: git tag v1.0.0 && git push origin v1.0.0.
3. Wait for the workflow to finish; a release named after the tag appears with platform-specific archives attached.