COMEDI_DATA_READ_HIN(3)

💖 COMEDI_DATA_READ_HIN 💖

okay so bestie, we're in the Comedi reference manual (that's the 3 in COMEDI_DATA_READ_HIN(3), mwah) and today's main character is a lil function that does ✨nothing✨ on purpose. yes really. let me explain.

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🎀 NAME 🎀

comedi_data_read_hint — literally just telling the driver which channel / range / aref you're about to read from next. that's it. that's the whole job. 💅

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✨ SYNOPSIS ✨

#include <comedilib.h>

int comedi_data_read_hint(comedi_t * device, unsigned int subdevice,
                          unsigned int channel, unsigned int range,
                          unsigned int aref);

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🦋 DESCRIPTION 🦋

so here's the vibe: you use this to prep an analog input for a call to comedi_data_read that you're gonna make right after. is it required? nope, not even a little. not necessary, bestie. BUT 🫶

it can be lowkey iconic when you wanna get rid of inaccuracies caused by insufficient settling times when you're switching the channel or the gain on an analog input. like, give the poor thing a second to compose itself, y'know?

what it actually does: it sets an analog input to the channel, range, and aref you specified — but it does not perform an actual analog-to-digital conversion. no conversion. zero. none. it's all setup, no payoff. it's giving… a rain check. 😭

alternatively, you could just use comedi_data_read_delayed, which sets up the input, pauses to let everything settle, then performs a conversion. so like, that one actually commit to the bit. 🍓

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👑 AUTHORS 👑

these are the legends, the founding mothers and fathers of the vibe:

• David Schleef <ds@schleef.org> — Author.
• Frank Mori Hess <fmhess@users.sourceforge.net> — Author.
• Herman Bruyninckx <Herman.Bruyninckx@mech.kuleuven.ac.be> — Author.
• Bernd Porr <tech@linux-usb-daq.co.uk> — Author.
• Ian Abbott <abbotti@mev.co.uk> — Author.
• Éric Piel <piel@delmic.com> — Author.

no cap, icon behavior from all six of them. 🌈

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💜 COPYRIGHT 💜

Copyright © 1998-2003 David Schleef
Copyright © 2001-2003, 2005, 2008 Frank Mori Hess
Copyright © 2002-2003 Herman Bruyninckx
Copyright © 2012 Bernd Porr
Copyright © 2012 Ian Abbott
Copyright © 2012, 2015 Éric Piel

This document is part of Comedilib. In the context of this document, the term "source code" as defined by the license is interpreted as the XML source. 📄✨

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, version 2.1 of the License. slay, open source.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 😭 (read the GNU Lesser General Public License for more deets, fr fr.)

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

⚠️ okay real talk for one sec: this is a legal section, so the all-caps words like WITHOUT ANY WARRANTY are doing actual legal work. i'm keeping them exactly, periodt. no vibes-based paraphrasing in the license, bestie, that's a whole different kind of undefined behavior. 💀

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and that's the page!! 🧚 from the Comedi crew, dated 03/20/2026, and yeah — we read COMEDI_DATA_READ_HIN(3) all the way to the end, so you know you're a real one. go prep your analog input, she deserves the head start. mwah 💋