v4l2_try_ext_ctrls(9)

📦 version 7.3.1, in nixpkgs unstable

💅 v4l2_try_ext_ctrls(9) 💅

okay so welcome to the Kernel API Manual, bestie — this is the page for v4l2_try_ext_ctrls, and yes we're gonna get through it together, hand in hand 🫶

✨ NAME ✨

v4l2_try_ext_ctrls — the helper function that implements the :ref:VIDIOC_TRY_EXT_CTRLS <vidioc_g_ext_ctrls>`` ioctl. that's it, that's the job, and it does it slayfully 👑

🌸 SYNOPSIS 🌸

int v4l2_try_ext_ctrls (struct v4l2_ctrl_handler *hdl , struct
video_device *vdev , struct media_device *mdev , struct
v4l2_ext_controls *c );

like, four arguments, one int coming back. no cap, that's the whole signature 💖

🎀 ARGUMENTS 🎀

  • hdl — a pointer to struct v4l2_ctrl_handler. the control handler in question, the main character of this whole situation ✨
  • vdev — a pointer to struct video_device. your video device, showing up to the group chat 🦋
  • mdev — a pointer to struct media_device. the media device, also invited 💜
  • c — a pointer to struct v4l2_ext_controls. the extended controls struct, holding all the actual control vibes 🎀

🔥 DESCRIPTION 🔥

so here's the one (1) behavioural fact on this page and honestly it's giving plot twist: if hdl == NULL then they will all return -EINVAL. that's the rule, that's the whole rule, and it's not negotiable ngl. no handler, no dice, error out with -EINVAL 💀

🦋 SEE ALSO 🦋

the kernel file in question is ./include/media/v4l2-ctrls.h — go read it, it's iconic 🌈. and now for the extended friend group, in the exact order they were introduced:

like. seventy-six of them. we ate that list fr fr 🍓

💡 friendly reminder bestie: the only behaviour documented on this page is that hdl == NULL makes them all return -EINVAL. don't go inventing extra lore, iykyk 🙈

and that's the page!! mwah 💋 this gem lives in the source dir ./include/media, and it's dated October 2026 — so yeah, she's from the future, main character energy only 👑💖 bye bestie, go write some slay control code 🧚✨

📦 where this page comes from