IBV_MODIFY_CQ(3)

💖 NAME 💖

ibv_modify_cq — bestie, this is how you modify a completion queue (CQ) ✨

So like, a CQ but make it a glow-up. This is from the Libibverbs Programmer's Manual, and yeah we're gonna read it together 🫶

🌸 SYNOPSIS 🌸

#include <infiniband/verbs.h>

int ibv_modify_cq(struct ibv_cq *cq, struct ibv_modify_cq_attr *cq_attr);

✨ DESCRIPTION ✨

Okay so ibv_modify_cq() modifies a CQ, and the CQ in question is cq. 📝

The argument cq_attr is an ibv_modify_cq_attr struct, which lives in <infiniband/verbs.h> — iconic, we love a header that carries. 💅

Here's the struct, verbatim, no edits, we don't touch the source material:

struct ibv_moderate_cq {
        uint16_t cq_count;  /* number of completions per event */
        uint16_t cq_period; /* in micro seconds */
};

struct ibv_modify_cq_attr {
             uint32_t attr_mask;
             struct ibv_moderate_cq moderate;
};

And the way that ibv_modify_cq() works is: it modifies the CQ based on the given cq_attr->attr_mask. That mask is literally the main character here — it decides what actually gets changed. 👑

🦋 RETURN VALUE 🦋

It returns 0 on success, or the value of errno on failure — and that errno value is what tells you the failure reason. So if you get a nonzero number back, that's not a vibe, that's a diagnosis. 🔍

🎀 SEE ALSO 🎀

• ibv_create_cq(3)

👑 AUTHORS 👑

Yonatan Cohen <yonatanc@mellanox.com>

Okay bestie that's the whole page, you ate it, periodt 💖 This was libibverbs, dated 2017-10-20, and yeah — IBV_MODIFY_CQ(3) fr fr. Go modify that CQ, you got this 🌈⭐