iio_read_channel_ext_info(9)

📦 version 7.3.1, in nixpkgs unstable

💅 iio_read_channel_ext_info — bestie's guide to the kernel API manual

Okay so, real talk: this page is literally from the Kernel API Manual, and it's all about iio_read_channel_ext_info — the function that reads an ext_info attribute off a given channel. That's the whole vibe. Let's get into it ✨

✨ SYNOPSIS ✨

ssize_t iio_read_channel_ext_info (struct iio_channel *chan , const char
*attr , char *buf );

Yes bestie, that's the whole signature, don't come for me about the line break, it's exactly how it's written 🫶

🎀 ARGUMENTS 🎀

  • chan — the channel being queried. Like, which one are we even talking about? This one. 👑
  • attr — the ext_info attribute you want to read. Pick your fighter.
  • buf — where the attribute value gets stashed. Important deets: it's assumed to hold at least PAGE_SIZE bytes and to be aligned at PAGE_SIZE. So don't be out here handing it a tiny little buffer, that's not the move 😭

🌸 DESCRIPTION 🌸

So this returns the number of bytes written to buf — and like, note the parenthetical because it's doing a lot of work: perhaps without zero termination, and honestly it need not even be a string. Not everything has to be a string, okay?? Let it be mysterious 💅

Or, plot twist, it returns an error code. That's it, that's the function. Simple, iconic, does exactly one thing. Periodt.

Fr fr though: that PAGE_SIZE size-and-alignment assumption on buf is not a suggestion, it's a whole requirement. Respect it or enjoy your undefined behaviour energy 💀

🦋 SEE ALSO 🦋

Kernel file ./include/linux/iio/consumer.h, plus literally the entire friend group:

⭐ the sign-off ⭐

This little masterpiece lives under ./include/linux/iio in the source tree, dated October 2026, and it's iio_read_channel_ext_info(9) through and through. Go read the source, bestie, it's giving main character energy 🌈💖

📦 where this page comes from