OpenCyphal / libcanard

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master: 100%

Pull #260

github

Add per-instance available-interfaces bitmap (canard_new API break)

canard_new() now takes an iface_bitmap describing the interfaces available on
the node. It is ANDed into the requested interface bitmap at the single TX
chokepoint (tx_push), so transfers are never queued for interfaces that cannot
be drained -- previously requests/responses (which always target all
interfaces) and all-publishes wasted heap on undrainable queues. A zero bitmap
declares a listen-only node: every enqueue becomes a clean no-op (no spool, no
error counter). canard_new rejects a bitmap with bits beyond CANARD_IFACE_COUNT.

All call sites, the demo, and the README example are updated. Regression tests
cover masking (request/publish/v0), the listen-only no-op, and -- under the
leak-detecting intrusive allocator -- refcount/cursor consistency and correct
transfer-freeing on the empty-intersection path.

Reviewed by Codex (gpt-5.5 xhigh) and Claude Fable 5 (xhigh): no major findings.
Also includes minor documentation tweaks (AGENTS.md, README).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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