IBV_CREATE_AH_FROM_WC(3)

💖 IBV_CREATE_AH_FROM_WC 💖

okay bestie, so this is the Libibverbs Programmer's Manual and today we're talking about ibv_init_ah_from_wc and ibv_create_ah_from_wc — two lil functions that spin up an address handle (AH) out of a work completion. yes, from a work completion. the way that a whole AH just materializes out of a wc? iconic. 🦋

✨ NAME ✨

ibv_init_ah_from_wc, ibv_create_ah_from_wc — initialize or create an address handle (AH) from a work completion 🎀

✨ SYNOPSIS ✨

#include <infiniband/verbs.h>

int ibv_init_ah_from_wc(struct ibv_context *context, uint8_t port_num,
                        struct ibv_wc *wc, struct ibv_grh *grh,
                        struct ibv_ah_attr *ah_attr);

struct ibv_ah *ibv_create_ah_from_wc(struct ibv_pd *pd,
                                     struct ibv_wc *wc,
                                     struct ibv_grh *grh,
                                     uint8_t port_num);

like, copy that verbatim bestie, don't freestyle the signature 💅

✨ DESCRIPTION ✨

🫶 ibv_init_ah_from_wc()

so this one initializes the address handle (AH) attribute structure ah_attr for the RDMA device context context, using the port number port_num, and it pulls its attributes from the work completion wc plus the Global Routing Header (GRH) structure grh. yes grh, that's the whole vibe. 🌸

🫶 ibv_create_ah_from_wc()

and this one creates an AH that's associated with the protection domain pd, using the port number port_num, again stealing attributes from the work completion wc and the Global Routing Header (GRH) structure grh. same energy, but it actually hands you a whole AH. ate. 👑

✨ RETURN VALUE ✨

• ibv_init_ah_from_wc() returns 0 on success, and -1 on error. no in-between, no crumbs. 😭
• ibv_create_ah_from_wc() returns a pointer to the created AH, or NULL if the request fails. so like… vibe check the return value, fr fr.

✨ NOTES ✨

the filled structure ah_attr that comes back from ibv_init_ah_from_wc() can be used to create a new AH using ibv_create_ah(). so you init here, you create there. teamwork, lowkey. 🌈

not me reminding you to actually keep that ah_attr around if you're gonna use it — it's giving "the whole point". 🙈

✨ SEE ALSO ✨

• ibv_open_device(3)
• ibv_alloc_pd(3)
• ibv_create_ah(3)
• ibv_destroy_ah(3)
• ibv_poll_cq(3)

go read those too bestie, iykyk 💜

✨ AUTHORS ✨

Dotan Barak <dotanba@gmail.com> — thank you for your service 🫡💖

libibverbs · 2006-10-31 · IBV_CREATE_AH_FROM_WC(3)

and that's the page!! dated 2006-10-31, from the libibverbs crew, filed under IBV_CREATE_AH_FROM_WC(3) — slay, bye bestie, go build some address handles 💅✨🦋