comedi_chan..._is_external(9)

📦 version 7.3.1, in nixpkgs unstable

💅 comedi_chan..._is_external(9) — like, the Kernel API Manual one, bestie ✨

okay so real talk, this page is titled comedi_chan..._is_external(9) and it lives in the Kernel API Manual, and it's about one (1) tiny little question: is this channel's range externally referenced or not? that's it. that's the whole vibe. 🎀

🌸 NAME 🌸

comedi_chan_range_is_external — bestie, it tests if a channel-specific range is external. no cap, that's the whole job. ✨

🦋 SYNOPSIS 🦋

bool comedi_chan_range_is_external (struct comedi_subdevice *s ,
unsigned int chan , unsigned int range );

it hands you back a bool, and it takes three things. we'll get to those. 🫶

🎀 ARGUMENTS 🎀

  • s — the COMEDI subdevice. this is your main character, the struct you're interrogating 💅
  • chan — the channel number. which channel are we snooping on 👀
  • range — the index of the range within a range table. like, which slot in the list, not the value itself, iykyk 🌸

⭐ DESCRIPTION ⭐

so what does it actually do? it tests whether a range is externally referenced — and the way it checks is by looking at whether that range's RF_EXTERNAL flag is set. that's the whole test. flag set → external energy. flag not set → not external energy. iconic, honestly. 🔥

⚠️ okay important caveats, listen up bestie — this function assumes chan and range are valid. it does not validate them for you, it just trusts you. and it only works for subdevices with a channel-specific range table list. anything else and, well, it's giving undefined vibes. 🙈

💀 RETURN 💀

  • true if the range is bipolar.
  • false if the range is unipolar.

that's literally what the page says, so that's literally what I'm telling you. periodt. ✨

🔮 SEE ALSO 🔮

the whole friend group, in the kernel file ./include/linux/comedi/comedidev.h:

like, the entire roster. go read them, they're all right there. 🧚

okay that's the whole page!! mwah 💖 this one came out of ./include/linux/comedi and the date on it is October 2026, so if you're reading this in some other timeline, that's on you bestie — stay slay, stay external-flag-aware, and go check your RF_EXTERNAL bits. 👑🌈⭐

📦 where this page comes from