Rust, C, and Mixed-Language Workspaces

The anatomy does not change with the language: node packages hold code, the bringup holds configuration, an entry per image. This page is what changes — per language — inside that fixed shape.

Rust

Scaffold the whole workspace in Rust, or add Rust node packages to an existing one:

nros new my_robot --workspace --lang rust      # whole workspace
nros new my_node --component --lang rust       # one node pkg, added under src/

A Rust node package is a library crate carrying nros::node!(YourNode); the entry collapses to one line:

#![allow(unused)]
fn main() {
nros::main!(launch = "demo_bringup", spin = "forever");
}

Two Rust-specific facts:

• nros sync before the first build, and again after editing .msg files or moving the checkout. It generates the message crates and the [patch.crates-io] table that maps nros dependencies to your checkout — cargo cannot resolve the workspace without it. C and C++ never need this; their codegen runs inside CMake.
• The RMW is spelled in three places (the bringup’s system.toml, the entry’s board-crate feature, the nros facade feature). The scaffold bakes all three from --rmw; changing it later is the checklist in Switching RMW in Config.

C

C node packages join a workspace the same way:

nros new my_c_node --component --lang c

A C node package is the declarative component shape — a configure function binding callbacks through nros/nros.h — built by the same per-package CMake as C++. There is no C workspace scaffold; start from the C++ workspace (nros new --workspace) and add C packages, which is also what the in-tree reference does.

Mixed — and why it just works

Languages mix per package, not per file, and the bringup does not care: a [[component]] row names a package and a class/entry point, whatever implements it. The in-tree reference workspace (examples/workspaces/mixed/) runs a C talker, a C++ listener, and a Rust heartbeat under one C++ entry:

mixed/src/
├── c_talker_pkg/          # C — publishes std_msgs/Int32 on /chatter
├── cpp_listener_pkg/      # C++ — subscribes
├── rust_heartbeat_pkg/    # Rust — a timer callback
├── demo_bringup/          # one system.toml for all three
└── native_entry/          # one C++ entry boots them together

Copy it out as a starting point if your project is mixed from day one.

Next

• Mixed-language workspaces, in depth
• C / C++ multi-node workspaces
• Node packages