STRUCT V4L2_SUBSCRIBED_EVENT(9)

📦 version 7.3.1, in nixpkgs unstable

✨ struct v4l2_subscribed_event(9) ✨

okay so this is from the Kernel API Manual, and we're talking about the struct with the longest name in the group chat: struct v4l2_subscribed_event. bestie. it's the internal struct that represents a subscribed event. iykyk 💅

🌸 NAME 🌸

struct v4l2_subscribed_event — Internal struct representing a subscribed event. that's literally it, that's the whole vibe. 🫶

🦋 SYNOPSIS 🦋

struct v4l2_subscribed_event {
    struct list_head        list;
    u32 type;
    u32 id;
    u32 flags;
    struct v4l2_fh          *fh;
    struct list_head        node;
    const struct v4l2_subscribed_event_ops *ops;
    unsigned int            elems;
    unsigned int            first;
    unsigned int            in_use;
    struct v4l2_kevent      events[];
 };

no cap, look at that flexible array member at the end, it's giving main character energy 🌈

🎀 Members 🎀

okay let's go member by member, no skipping, we do not skip in this house 😤

  • list — the list node for the v4l2_fh->subscribed list. it's the little hook that keeps you in the friend group 🫂
  • type — event type. what kind of event are we even talking about, y'know?
  • id — the associated object ID (e.g. control ID). 0 if there isn't any. so if you see a zero, they're single and ready to mingle 💀
  • flags — a copy of v4l2_event_subscription->flags. copy, not reference. respect the clone 🧚
  • fh — the filehandle that subscribed to this event. the original subscriber, the one who hit follow first 👑
  • node — list node that hooks into the object's event list (if there is one). note the if there is one, sometimes there just isn't, and that's fine 💜
  • ops — v4l2_subscribed_event_ops. the ops. the whole personality of this thing honestly.
  • elems — the number of elements in the events array. count 'em, bestie 🔢
  • first — the index of the events containing the oldest available event. grandma of the array, respect her 🌸
  • in_use — the number of queued events. how many are currently in the queue, lining up like it's a club 🍓
  • events — an array of elems events. yes, elems again. they're linked like that 💖

⭐ SEE ALSO ⭐

the kernel file is ./include/media/v4l2-event.h — go read her, she's iconic ✨

and here's the whole extended friend group, every single one, no leaving anyone out:

and that's the tea ☕ go subscribe to an event, bestie, you've got this 💅🔥

signing off from ./include/media, dated October 2026 — mwah, love u, read ur headers 🎀💖🦋

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