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Fluss C++ CMake Usage Guide (System / Build Modes)

Audience

  • C++ application teams building bindings/cpp with CMake
  • Maintainers evolving Fluss C++ dependency provisioning

Scope

  • Build system covered by this document: CMake
  • Dependency modes covered by this document: system/build

Current tested baselines:

  • protoc: 3.25.5
  • arrow-cpp: 19.0.1

Notes:

  • CMake currently warns (does not fail) when local protoc/Arrow versions differ from the baselines.
  • protoc is required because Rust prost-build runs during the C++ build.

Common Prerequisites

  • Rust toolchain (cargo in PATH, or set CARGO=/path/to/cargo)
  • protoc in PATH (required for system mode; build mode can auto-download via bindings/cpp/scripts/ensure_protoc.sh)
  • C++17 compiler
  • CMake 3.22+

Examples below use bindings/cpp as the source directory.

Mode 1: system

Use this mode when the environment already provides Arrow C++.

Configure

cmake -S bindings/cpp -B /tmp/fluss-cpp-cmake-system \
  -DFLUSS_CPP_DEP_MODE=system \
  -DFLUSS_CPP_ARROW_SYSTEM_ROOT=/path/to/arrow/prefix

Typical prefixes:

  • Ubuntu package install: /usr
  • Custom install prefix: /usr/local or /opt/arrow

Build

cmake --build /tmp/fluss-cpp-cmake-system --target fluss_cpp -j

Mode 2: build

Use this mode when Arrow C++ is not preinstalled and CMake should fetch/build it.

Configure (with auto-downloaded protoc)

PROTOC_BIN="$(bash bindings/cpp/scripts/ensure_protoc.sh --print-path)"
export PATH="$(dirname "$PROTOC_BIN"):$PATH"

Then configure:

cmake -S bindings/cpp -B /tmp/fluss-cpp-cmake-build \
  -DFLUSS_CPP_DEP_MODE=build

Optional overrides:

  • -DFLUSS_CPP_ARROW_VERSION=19.0.1
  • -DFLUSS_CPP_ARROW_SOURCE_URL=... (internal mirror or pinned archive)
  • -DFLUSS_CPP_PROTOBUF_VERSION=3.25.5 (baseline warning only)

If your environment needs a proxy for CMake/FetchContent downloads, export standard proxy vars before configure/build:

export http_proxy=http://host:port
export https_proxy=http://host:port
export HTTP_PROXY="$http_proxy"
export HTTPS_PROXY="$https_proxy"

Build

cmake --build /tmp/fluss-cpp-cmake-build --target fluss_cpp -j

This mode is slower on first build because it compiles Arrow C++ from source.

Repository-local Validation (Direct Commands)

Validate system mode

PROTOC_BIN="$(bash bindings/cpp/scripts/ensure_protoc.sh --print-path)"
export PATH="$(dirname "$PROTOC_BIN"):$PATH"
cmake -S bindings/cpp -B /tmp/fluss-cpp-cmake-system \
  -DFLUSS_CPP_DEP_MODE=system \
  -DFLUSS_CPP_ARROW_SYSTEM_ROOT=/tmp/fluss-system-arrow-19.0.1
cmake --build /tmp/fluss-cpp-cmake-system --target fluss_cpp -j

Validate build mode

PROTOC_BIN="$(bash bindings/cpp/scripts/ensure_protoc.sh --print-path)"
export PATH="$(dirname "$PROTOC_BIN"):$PATH"
cmake -S bindings/cpp -B /tmp/fluss-cpp-cmake-build \
  -DFLUSS_CPP_DEP_MODE=build
cmake --build /tmp/fluss-cpp-cmake-build --target fluss_cpp -j

Troubleshooting

  • cargo not found
    • Install Rust toolchain or set CARGO=/path/to/cargo.
  • protoc not found
    • Install protoc and ensure it is in PATH.
    • For build mode, use bindings/cpp/scripts/ensure_protoc.sh and prepend the returned path to PATH.
  • arrow/c/bridge.h not found (build mode)
    • Reconfigure after updating to the latest bindings/cpp/CMakeLists.txt; build mode now adds Arrow source/build include dirs explicitly.
  • Long first build in build mode
    • Expected. Arrow C++ source build dominates wall time.