nros::Result wraps an nros::ErrorCode (a strongly-typed int32_t enum). Use result.ok() for success checks, or the NROS_TRY(expr) macro to short-circuit on the first error.

ErrorCode Table

Raw	`nros::ErrorCode`	Cause	Recovery
`0`	`Ok`	Success	—
`-1`	`Error`	Generic failure not covered by a specific code.	Inspect logs and the function-specific docs.
`-2`	`Timeout`	Operation deadline elapsed before completion.	Retry, increase the timeout, or verify the remote peer is reachable.
`-3`	`InvalidArgument`	Null pointer, empty topic name, or out-of-range value.	Validate inputs before the call.
`-4`	`NotInitialized`	`nros::init()` was never called or returned an error; or the entity (publisher, subscription, …) is in a default-constructed state.	Call `nros::init()` first; check `is_valid()`.
`-5`	`Full`	Static pool exhausted (executor slots, subscription buffers, parameter table, …).	Raise the matching `NROS_*` env var and rebuild. See Configuration.
`-6`	`TryAgain`	Transient — no data ready yet (non-blocking take).	Retry on the next executor tick.
`-7`	`Reentrant`	A blocking call was made from inside a callback.	Re-architect to use the executor or an async path.
`-100`	`TransportError`	Underlying transport rejected the operation.	Often paired with a `_Z_ERR_*` log line; see Troubleshooting.

NROS_TRY

nros::Result init_pubsub(nros::Node& node) {
    nros::Publisher<MyMsg> pub;
    NROS_TRY(node.create_publisher(pub, "/topic"));   // early-return on error
    NROS_TRY(pub.publish(seed_msg));
    return nros::Result::success();
}

NROS_TRY(expr) evaluates expr once and, if the result is not success, returns it from the enclosing function. Only valid inside functions that themselves return nros::Result.

Pattern: Manual Error Handling

auto ret = node.create_publisher(pub, "/topic");
if (!ret.ok()) {
    std::fprintf(stderr, "create_publisher failed: %d\n", ret.raw());
    return ret;
}

Result::raw() returns the underlying int32_t for logging. Result::code() returns the typed ErrorCode for switch dispatch.

zenoh-pico Underlying Errors

TransportError typically wraps one of these zenoh-pico return codes:

Code	Name	Meaning
-3	`_Z_ERR_TRANSPORT_OPEN_FAILED`	Cannot connect to router
-73	`_Z_ERR_SESSION_CLOSED`	Session closed after failure
-78	`_Z_ERR_SYSTEM_OUT_OF_MEMORY`	Allocation failed
-100	`_Z_ERR_TRANSPORT_TX_FAILED`	Transport transmission failed
-128	`_Z_ERR_GENERIC`	Generic error

ErrorCode Table

NROS_TRY

Pattern: Manual Error Handling

zenoh-pico Underlying Errors

See Also