API Reference

CoContext

Method	Returns	Description
`create_task(task)`	`Task<T>`	Start a coroutine
`subscribe<MsgT>(topic, qos)`	`shared_ptr<TopicStream<MsgT>>`	Subscribe to a topic
`create_timer(period)`	`shared_ptr<TimerStream>`	Create a periodic timer stream
`create_service<SrvT>(name, cb)`	`shared_ptr<Service<SrvT>>`	Create a coroutine service server
`create_action_server<ActT>(name, cb)`	`shared_ptr<Server<ActT>>`	Create a coroutine action server
`wait_for_service(client, timeout)`	awaitable `Result<void>`	Wait for a service
`send_request<SrvT>(client, req)`	awaitable `Response`	Call a service
`wait_for_action(client, timeout)`	awaitable `Result<void>`	Wait for an action server
`send_goal<ActT>(client, goal)`	awaitable `Result<shared_ptr<GoalStream>>`	Send an action goal
`sleep(duration)`	awaitable `void`	Async sleep
`poll_until(pred, interval, timeout)`	`Task<Result<void>>`	Poll until predicate is true or timeout
`wait_for(awaitable, timeout)`	`Task<Result<T>>`	Race an awaitable against a timeout
`post(fn)`	`void`	Post a callback to the executor thread (thread-safe)
`node()`	`Node&`	Access the underlying node

Function	Returns	Description
`create_single_goal_action_server<ActT>(ctx, name, cb)`	`shared_ptr<Server<ActT>>`	Single-goal action server with preemption
`when_all(awaitables...)`	awaitable `tuple<Ts...>`	Await all tasks/awaitables concurrently
`when_any(awaitables...)`	awaitable `variant<Ts...>`	Race tasks/awaitables, return first result
`shield(task)`	awaitable `T`	Protect a task from parent cancellation

Method	Returns	Description
`operator bool()`	`bool`	`true` if the task holds a valid coroutine (not moved-from)
`done()`	`bool`	`true` if the coroutine has completed (`false` for null tasks)
`result()`	`T&`	Get the result of a completed `Task<T>` (rethrows if exception)
`cancel()`	`void`	Request cancellation via `CancelledException`

Method	Returns	Description
`ok()`	`bool`	`true` if the operation succeeded
`timeout()`	`bool`	`true` if the operation timed out
`value`	`std::optional<T>`	The result value (present when `ok()` is `true`)

Method	Returns	Description
`goal()`	`const Goal&`	Access the goal request
`is_canceling()`	`bool`	Check if cancellation was requested
`publish_feedback(fb)`	`void`	Send feedback to the client
`abort()`	`void`	Abort the goal

Method	Returns	Description
`set()`	`void`	Signal the event, resuming all waiters
`clear()`	`void`	Reset the event so future `wait()` calls will suspend
`wait()`	awaitable `void`	Suspends until the event is set
`is_set()`	`bool`	Check the current state

Method	Returns	Description
`lock()`	awaitable `void`	Suspends until the lock is acquired
`unlock()`	`void`	Release the lock, resuming the next waiter
`is_locked()`	`bool`	Check the current state

Method	Returns	Description
`send(value)`	`void`	Send a value (thread-safe)
`close()`	`void`	Signal end of stream
`next()`	awaitable `optional<T>`	Receive the next value (`nullopt` when closed)

Method	Returns	Description
`TfBuffer(ctx)`	--	Construct with a `CoContext`; starts a listener thread
`lookup_transform(target, source)`	`optional<TransformStamped>`	Sync lookup of latest transform
`lookup_transform(target, source, time)`	awaitable `TransformStamped`	Async lookup; suspends until available