v4l2_event_subscribe(9)

📦 version 7.3.1, in nixpkgs unstable

💅 v4l2_event_subscribe(9) — the Kernel API Manual, bestie edition ✨

Okay so this is a page straight out of the Kernel API Manual, and it's literally about subscribing to an event. Yes, like hitting that subscribe button but for kernel events 🫶

🌸 NAME 🌸

v4l2_event_subscribe — the one where you subscribe to an event. That's it, that's the whole name. Iconic behavior honestly 💅

✨ SYNOPSIS ✨

int v4l2_event_subscribe (struct v4l2_fh *fh , const struct
       v4l2_event_subscription *sub , unsigned int elems , const struct
       v4l2_subscribed_event_ops *ops );

Look at that signature, she's serving. Four parameters, returns an int. Not me being obsessed with a function prototype 😭

🎀 ARGUMENTS 🎀

Okay bestie, let's meet the cast:

  • fh — a pointer to struct v4l2_fh. She's the file handle, the main character of this whole operation 👑
  • sub — a pointer to struct v4l2_event_subscription. This is the actual subscription, the thing you're signing up for 💖
  • elems — the size of the events queue. That's how much room your events get to hang out in there 🌈
  • ops — a pointer to struct v4l2_subscribed_event_ops. The operations posse, the support squad 🦋

🧚 DESCRIPTION 🧚

NOTE: if elems is zero, the framework will fill in a default value, which is currently 1 element. So like, zero doesn't mean "no room bestie", it means "the framework picks for you" and right now that pick is literally 1 🙈

That's genuinely the whole vibe of the description — no cap, don't skip the note, it's the entire point of the page ✨

💜 SEE ALSO 💜

Go look at the kernel file ./include/media/v4l2-event.h, and also these absolute icons:

That's the whole friend group, go read all of them, iykyk 🔥

And that's the page bestie!! 💖✨ This one lives under ./include/media, dated October 2026, and it's v4l2_event_subscribe(9) all the way through — mwah, slay, see u in the kernel 🎀💅🫶

📦 where this page comes from