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Bazel build

flight-cpp is a Bazel module as well as a CMake project. The runtime and tests have no third-party dependencies; the build graph pins rules_cc, which supplies the C++ rules removed from Bazel's built-ins. Bazelisk reads .bazelversion to select Bazel 9.2.0.

Local build and tests

The public targets corresponding to CMake's Flight::Cpp and Flight::C are //:cpp and //:c. Compatibility aliases //:flight_cpp and //:flight_cpp_c are also public.

Bazel C++ toolchains do not expose a portable target attribute for selecting a language dialect. The checked-in .bazelrc therefore enables Bazel's host-platform configuration and selects C++20 for GCC/Clang on Linux, macOS, FreeBSD, and OpenBSD and for Visual C++ on Windows. A clean local checkout can run the core graph directly:

cd flight-cpp
bazel build //:cpp //:c
bazel test //:tests

The optional --config=local-posix adds compile and link pthread flags for a local toolchain that still needs them. The C++20 selection itself is automatic and does not require callers to remember a named configuration.

//:tests covers the runtime, compiler-generated source, C ABI, all public headers in isolation, and C and C++ public-surface consumers. The underlying labels are available for focused runs:

  • //examples:tween
  • //tests:runtime_test
  • //tests:runtime_conformance_test
  • //tests:generated_runtime_test
  • //tests:c_api_test
  • //tests:c_api_thread_test
  • //tests:public_header_tests
  • //tests/consumer:cpp_consumer_test
  • //tests/consumer:c_consumer_test

The performance smoke test is intentionally excluded from wildcard and suite runs by its manual tag. Run it explicitly in an optimized configuration:

bazel test --config=local-posix --config=release //benchmarks:runtime_benchmark

SDL host

The optional SDL host pins SDL 3.4.10 and builds it from source with rules_foreign_cc. Its targets are manual, so the dependency-free runtime suite above does not download or build SDL. With CMake, Ninja, Make, M4, and pkg-config available as build tools, run the host test and the offscreen GL example with:

bazel test --config=local-posix //tests:host_sdl_test
SDL_VIDEODRIVER=offscreen SDL_AUDIODRIVER=dummy \
  bazel run --config=local-posix //examples:tween_sdl_gl -- --smoke

Applications depend on //:host_sdl, //:host_sdl_image, //:host_sdl_gl, or //:host_sdl_wgpu. The image target is linked transitively by both graphics paths. The Vulkan adapter remains CMake-only until its SDK is represented as a pinned Bazel dependency.

Registered toolchains and platforms

Production and cross builds should make the C++20 dialect, compiler, standard library, sysroot, linker, and target constraints part of a registered C++ toolchain. Select that toolchain through the normal Bazel resolution surface:

bazel test --noenable_platform_specific_config //:tests \
  --platforms=@company_platforms//cpp:linux_x86_64 \
  --extra_toolchains=@company_toolchains//cpp:clang_linux_x86_64

Disabling the automatic host configuration prevents a host compiler flag from leaking into a cross or remote action; the selected toolchain must then declare C++20 itself. The target graph remains independent of the compiler and platform labels. Put personal defaults in the ignored .bazelrc.local; checked-in cross/remote automation should pass platform and toolchain labels explicitly.

//:c is a linked static C ABI library. The Bazel graph does not yet force a shared-library artifact: a correct portable shared target must give the adapter private export definitions and its consumers public import definitions, then be tested across ELF, Mach-O, and PE/COFF. An ad hoc cc_binary(linkshared=True) would not meet that contract on Visual C++. Until that split exists, use the CMake BUILD_SHARED_LIBS build when a loadable C ABI artifact is required.

Reproducibility policy

The module pins its Bazel release and rules_cc version, contains an explicit source graph, disables build stamping, and gives tests a fixed UTC/C process environment. Strict action environments keep undeclared machine state out of compile and link actions. Release builds use --config=release; CI can add --config=ci to retain all failures from a test sweep.

MODULE.bazel.lock records the complete external build dependency graph, and .bazelrc makes drift an error. If another external build dependency is introduced, its version and integrity must be pinned in MODULE.bazel and the lock must be deliberately regenerated with Bazel 9.2.0. A consuming repository owns its own module lock and may substitute its registered platforms and toolchains without changing flight-cpp.

Bazel cache keys include the selected platform and toolchain. Reproducibility therefore means identical outputs for identical source, Bazel, flags, platform, and toolchain inputs; it does not assert byte equality between different C++ compilers or standard libraries.