Struct rmw_publisher_t 

#[repr(C)]
pub struct rmw_publisher_t {
    pub topic_name: *const c_char,
    pub type_name: *const c_char,
    pub qos: rmw_qos_profile_t,
    pub can_loan_messages: bool,
    pub _reserved: [u8; 7],
    pub backend_data: *mut c_void,
}

Publisher entity.

Created by vtable->create_publisher; destroyed by vtable->destroy_publisher. The runtime owns the storage; the runtime fills topic_name / type_name / qos before the create call. The backend writes backend_data.

can_loan_messages matches upstream rmw_publisher_t’s field of the same name — true means the backend exposes the loan_publish / commit_publish primitive (Phase 99).

The runtime DERIVES it; a backend does not write it (issue 0814). Its value is exactly vtable->borrow_loaned_message != NULL, because that is the same fact, and a fact with two spellings drifts — this one had drifted in both directions at once. Anything a backend writes here is overwritten.

This paragraph used to read “the runtime reads it once at create time and picks the publish path accordingly; no per-call probe”. That was never true: nothing has ever branched on the field, and the publish path is chosen per call from vtable->borrow_loaned_message itself.

To refuse a loan for a PARTICULAR entity, return RMW_RET_UNSUPPORTED from borrow_loaned_message. The per-entity answer belongs on the call, which the runtime consults; not on this flag, which it does not.

Fields

topic_name: *const c_char

Topic name (borrowed; outlives the publisher).

type_name: *const c_char

ROS-2-style fully-qualified type name (e.g., "std_msgs/msg/Int32"). Borrowed; outlives the publisher.

qos: rmw_qos_profile_t

QoS subset honoured by this publisher.

can_loan_messages: bool

Backend exposes loan_publish / commit_publish (Phase 99). DERIVED by the runtime from vtable->borrow_loaned_message; a backend’s write is overwritten (issue 0814).

_reserved: [u8; 7]

Reserved for future fields; must be zero.

backend_data: *mut c_void

Opaque backend state. NULL if creation failed.

Trait Implementations

impl Clone for rmw_publisher_t

fn clone(&self) -> rmw_publisher_t

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for rmw_publisher_t

impl Debug for rmw_publisher_t

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.