Struct NrosTransportOps 

#[repr(C)]
pub struct NrosTransportOps {
    pub abi_version: u32,
    pub _reserved: u32,
    pub user_data: *mut c_void,
    pub open: unsafe extern "C" fn(user_data: *mut c_void, params: *const c_void) -> i32,
    pub close: unsafe extern "C" fn(user_data: *mut c_void),
    pub write: unsafe extern "C" fn(user_data: *mut c_void, buf: *const u8, len: usize) -> i32,
    pub read: unsafe extern "C" fn(user_data: *mut c_void, buf: *mut u8, len: usize, timeout_ms: u32) -> i32,
}

Phase 115.A — runtime-pluggable custom transport. Caller fills in the four fn pointers, hands the struct to set_custom_transport, and the active backend treats it as the read / write surface for every wire frame.

#[repr(C)] so this is the SAME struct that nros_transport_ops_t (C) and nros::TransportOps (C++) point at — single layout, no parallel definitions to drift.

Return-code conventions

open / write return NROS_RMW_RET_OK (== 0) on success and a negative nros_ret_t (see nros-rmw-cffi) on failure. read returns the non-negative byte count on success or a negative nros_ret_t on error / timeout.

Safety contract for the four fn pointers

• All callbacks receive user_data as their first argument. The pointer is whatever the caller stored at registration time; the runtime never dereferences it.
• buf / len describe a contiguous byte region the callback may read (write) or write (read). The callback must NOT retain pointers across the call.
• params (in open) is opaque per-transport metadata threaded through from set_custom_transport. May be NULL.

Fields

abi_version: u32

Phase 115.A.2 — ABI version. Consumers MUST fill in NROS_TRANSPORT_OPS_ABI_VERSION_V1; mismatched values are rejected at registration time with TransportError::IncompatibleAbi (NROS_RMW_RET_INCOMPATIBLE_ABI at the C boundary). Reserved for future minor-version detection — see the const’s doc-comment.

_reserved: u32

Phase 115.A.2 — reserved padding to keep the struct alignment-stable across appends. Must be zero.

user_data: *mut c_void

Opaque caller context, threaded back into every callback as the first argument. Lifetime: must outlive the transport’s active period (i.e. until close returns).

open: unsafe extern "C" fn(user_data: *mut c_void, params: *const c_void) -> i32

Open the underlying medium. params is opaque per-transport metadata (e.g. UART baud rate, USB-CDC endpoint id) supplied at registration time.

close: unsafe extern "C" fn(user_data: *mut c_void)

Tear the transport down. Complement of open. After close returns, the runtime will not invoke read or write on this transport unless set_custom_transport is called again.

write: unsafe extern "C" fn(user_data: *mut c_void, buf: *const u8, len: usize) -> i32

Send len bytes from buf. Returns 0 on success, negative nros_ret_t on failure. Must NOT block beyond a brief hardware retry; long blocking should surface as NROS_RMW_RET_TIMEOUT (-2).

read: unsafe extern "C" fn(user_data: *mut c_void, buf: *mut u8, len: usize, timeout_ms: u32) -> i32

Receive up to len bytes into buf within timeout_ms. Returns the non-negative byte count on success (may be less than len), or a negative nros_ret_t on error / timeout.

Trait Implementations

impl Clone for NrosTransportOps

fn clone(&self) -> NrosTransportOps

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for NrosTransportOps

impl Send for NrosTransportOps

impl Sync for NrosTransportOps