Build as a CMake subdirectory

This is the way to integrate nano-ros into a C or C++ project. The nano-ros repo ships a top-level CMakeLists.txt that exposes everything via add_subdirectory(...). No install step, no find_package(NanoRos), no install prefix removed every last trace of that pipeline.

Layout

my_app/
├── CMakeLists.txt
├── main.c
└── third_party/
    └── nano-ros/        # git clone / git submodule of this repo

User project CMakeLists.txt

cmake_minimum_required(VERSION 3.22)
project(my_app C)

# Pick platform + RMW BEFORE add_subdirectory.
set(NANO_ROS_PLATFORM posix)   # posix | freertos | nuttx | threadx | zephyr | baremetal
set(NANO_ROS_RMW     zenoh)    # zenoh | dds | xrce | cyclonedds

add_subdirectory(third_party/nano-ros nano_ros)

add_executable(my_app main.c)
target_link_libraries(my_app PRIVATE NanoRos::NanoRos)
nros_platform_link_app(my_app)

# Optional — generate C bindings for ROS 2 .msg / .srv / .action files.
# nros_generate_interfaces() is reachable in-tree once nano-ros has been
# add_subdirectory'd; no install step required.
nros_generate_interfaces(std_msgs DEPENDENCIES builtin_interfaces SKIP_INSTALL)
target_link_libraries(my_app PRIVATE std_msgs__nano_ros_c)

That’s the whole story for the host-POSIX / zenoh case. CMake’s transitive target propagation pulls in libnros_c.a, libnros_rmw_zenoh_staticlib.a, the POSIX platform shim, system libraries (pthread, dl, m), and the per-build nros_config_generated.h header automatically.

Cache variables

Variables MUST be set(...) BEFORE add_subdirectory(...) — the sub-project consumes them at include time.

What about installing?

deleted every install(...) rule. nano-ros is consumed in source form — never out of an installed prefix. If you need a shippable artefact, your user project owns the install layout; ship your binary, not nano-ros itself.

For RTOS users who want a more idiomatic surface than raw add_subdirectory, see the integration shells under integrations/<rtos>/ — they translate west / esp-idf / NuttX / PX4 manifests into the same root CMake. Each shell is a ~20-line wrapper around add_subdirectory(<repo>).

Worked example

The examples/native/c/talker/CMakeLists.txt is the canonical copy-out template — 20 lines including codegen + per-app fixup. All 83 in-tree C/C++ examples follow the same shape after.