v4l2_ctrl_notify_fnc(9)

📦 version 7.3.1, in nixpkgs unstable

💅 v4l2_ctrl_notify_fnc — like, the Kernel API Manual page, bestie ✨

Okay so real talk: this is the v4l2_ctrl_notify_fnc(9) page from the Kernel API Manual, and it's short but lowkey important, so let's get into it 🫶

🌸 NAME 🌸

v4l2_ctrl_notify_fnc — it's a typedef for the notify argument that comes with a function that should get called when a control value has changed. That's the whole vibe. You pass this, and whenever the control's value changes, the function goes off 🔥

✨ SYNOPSIS ✨

void v4l2_ctrl_notify_fnc (struct v4l2_ctrl *ctrl , void *priv );

I know, I know — spaces before the commas. Not me judging, that's literally just how it's written 💀 copy it exactly, no cap.

🎀 ARGUMENTS 🎀

  • ctrl — a pointer to struct v4l2_ctrl. Like, the control itself, the main character 👑
  • priv — the control's private data. Your little stash of personal stuff that rides along 🍓

🦋 DESCRIPTION 🦋

So this typedef definition is used as an argument to v4l2_ctrl_notify, and it's also used as an argument at struct v4l2_ctrl_handler. That's it, that's the tea ✨ Two places, icon behavior, periodt.

🌈 SEE ALSO 🌈

This is the part where I need you to hydrate, because it's a list — like a whole friend group of kernel symbols, and every single one of them is invited to the party 🎉

From the kernel file ./include/media/v4l2-ctrls.h:

Like I said — the whole group chat 💜

Bestie heads-up: this page is only the typedef definition. It's not a callable function with a body you run, so don't go looking for behavior that isn't here. The actual "call this when the value changes" mechanics live with the things listed above, fr fr 🧚

Okay that's the whole page, go touch some grass and then go read v4l2_ctrl_notify(9) 💖

— xoxo, from the ./include/media directory, dated October 2026, and this has been v4l2_ctrl_notify_fnc(9). slay 🎀

📦 where this page comes from