int2dds_ffi_vendor

ROS 2 vendor package that fetches the prebuilt int2DDS FFI library for the host platform at build time and exposes it to colcon/ament as an imported CMake target. It is the dependency boundary between the Rust int2DDS core (shipped as prebuilt binaries) and the C++ rmw_int2dds_cpp middleware.

What it does

1. Detects the host OS, architecture, and libc (gnu/musl).
2. Downloads the per-OS release asset from the int2dds_ffi_vendor releases page. That repository is the artifact host; this package’s source lives in rmw_int2dds.
3. Reads the bundled manifest, selects the artifact matching the host, and verifies its sha256.
4. Installs int2dds-ffi.h + the platform shared library as include/ + lib/.
5. Exports the imported target int2dds_ffi::int2dds_ffi.

Consuming it (downstream)

find_package(int2dds_ffi_vendor REQUIRED)
target_link_libraries(my_target int2dds_ffi::int2dds_ffi)

<!-- package.xml -->
<depend>int2dds_ffi_vendor</depend>

Release asset layout

One tarball per OS is published on the int2dds_ffi_vendor release tagged v${INT2DDS_FFI_VERSION} (see CMakeLists.txt). Each tarball bundles every architecture for that OS plus a manifest. Each architecture directory carries the real library plus the usual SONAME symlink chain:

int2dds-ffi-<version>-linux.tar.gz
├── int2dds-ffi.h                              # C API header
├── int2dds-ffi.manifest.yaml                  # per-arch file + sha256 + soname + min_glibc
├── LICENSE
├── linux-x86_64/                              # amd64, gnu
│   ├── libint2dds_ffi.so.<version>            #   real file
│   ├── libint2dds_ffi.so.0 -> .so.<version>   #   SONAME
│   └── libint2dds_ffi.so   -> .so.0           #   linker name
├── linux-x86_64-musl/                         # amd64, musl
├── linux-aarch64/                             # arm64, gnu
├── linux-aarch64-musl/                        # arm64, musl
└── linux-armhf/                               # armv7, gnu

int2dds-ffi.manifest.yaml:

name: int2dds-ffi
version: 0.1.1
artifacts:
  - os: linux
    arch: amd64
    triple: x86_64-unknown-linux-gnu
    file: linux-x86_64/libint2dds_ffi.so.0.1.1
    soname: libint2dds_ffi.so.0
    sha256: <hex>
    min_glibc: "2.34"
  ...

The file: value must match <subdir>/libint2dds_ffi.so.${INT2DDS_FFI_VERSION} exactly — that is the key the vendor package looks up to find the expected sha256. If it does not match, verification is skipped with a warning instead of failing.

Because the manifest already carries per-artifact sha256, the vendor package verifies integrity automatically — no SHA values need to be hard-coded here.

libc selection

The default is glibc (gnu), which is what ROS binaries target (Ubuntu 22.04 Jammy ships glibc 2.35 ≥ the artifacts’ min_glibc: 2.34). For a musl host:

colcon build --cmake-args -DINT2DDS_FFI_LIBC=musl

armhf ships only a gnu build.

Building against a locally built FFI

INT2DDS_FFI_TARBALL replaces the download with a tarball you already have — normally the one the int2DDS tree just produced:

colcon build --cmake-args \
  -DINT2DDS_FFI_TARBALL=/path/to/int2DDS/ffi/dist/int2dds-ffi-0.1.1-linux.tar.gz

Two reasons to reach for it. The obvious one is offline builds. The other is that the release tag does not identify the ABI: the v0.1.1 assets were rebuilt

File truncated at 100 lines see the full file

Changelog for package int2dds_ffi_vendor

Forthcoming

• Move the package into the rmw_int2dds repository, next to rmw_int2dds_cpp, so the two are released in lockstep. The prebuilt FFI tarballs are still published on the int2dds_ffi_vendor release page and are downloaded and sha256-verified at CMake configure time, unchanged.
• Contributors: Intellectus Corp.