Writing C extensions with the bocpy public C ABI

This skill is for writing a downstream C extension whose custom types must travel through bocpy's runtime — placed inside a Cown, scheduled with @when, or shipped via send/receive across worker sub-interpreters.

Read thinking-in-boc first. The C ABI does not change the BOC mental model. Your C type is still wrapped in a Cown, behaviors are still scheduled with @when, and ordering still comes from the cown graph — not from anything you do in C. The C ABI only buys you a safe, zero-copy way to cross the interpreter boundary; the choreography between behaviors is unchanged.

When you need this skill

You need a C extension that uses the bocpy public C ABI only when all three of the following are true: