COMEDI_SET_READ_SUBD(3)

💖 COMEDI_SET_READ_SUBD 💖

okay bestie, welcome to the comedi_set_read_subdevice page from the Comedi reference (section 3 of the manual, iykyk) 🎀 this is the one that picks which subdevice is doing your streaming input. slay.

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✨ NAME ✨

comedi_set_read_subdevice — sets the streaming input subdevice 🌸

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🦋 SYNOPSIS 🦋

#include <comedilib.h>

int comedi_set_read_subdevice(comedi_t * device,
                              unsigned int subdevice);

yep that's the whole vibe. two args, one little int coming back at you 💅

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🌈 STATUS 🌈

works for Linux "in-tree" Comedi since kernel version 3.19. no cap. ⭐

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👑 DESCRIPTION 👑

so like, comedi_set_read_subdevice takes subdevice and makes it the current “read” subdevice — but ONLY if that subdevice actually supports streaming input commands. vibe check required, fr fr.

if subdevice is already the current “read” subdevice? nothing happens. no action, zero, nada, it just sits there being iconic 🙈

and listen, this is the important part: changes are local to the open file description for this device. they have no effect on other open file descriptions for the underlying device node. so like, you do you, but your other fd's are NOT getting the memo 🫶

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💜 RETURN VALUE 💜

• On success, 0 is returned ✨
• On failure, -1 is returned 😭

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🎀 AUTHORS 🎀

the literal legends who built this:

• 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.

periodt. 👑

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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.

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. See the GNU Lesser General Public License for more details.

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.

real talk bestie: that whole "WITHOUT ANY WARRANTY" thing is not a joke, it's the actual license text, so pls read it and don't come for me 💀

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and that's the page!! this version is from 03/20/2026, Comedi, COMEDI_SET_READ_SUBD(3) — mwah, go set some subdevices 💅✨🦋