COMEDI_GET_BUFFER_WR(3)

✨ COMEDI_GET_BUFFER_WR(3) ✨

okay bestie, welcome to the Comedi reference manual, section 3 💖 this one's about comedi_get_buffer_write_offset and it's short, sweet, and lowkey iconic.

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🎀 NAME 🎀

comedi_get_buffer_write_offset — streaming buffer write offset, fr fr

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🦋 SYNOPSIS 🦋

#include <comedilib.h>

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

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🌸 DESCRIPTION 🌸

so here's the vibe: you call comedi_get_buffer_write_offset on a subdevice that already has a Comedi command in progress, and it hands you the current write position in the streaming buffer 🙌

and that position? it's an offset in bytes from the start of the buffer, no cap.

the position wraps around to 0 once it hits the buffer size — like a lil carousel 🎠 so don't be shocked when it resets, that's just the behavior.

heads up bestie: this offset is only useful for memory mapped buffers. if you're not on a mmap'd buffer, this isn't giving what you want 💅

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👑 RETURN VALUE 👑

• on success → returns the current write position as an offset in bytes from the start of the buffer ✨
• on failure → returns -1 😭

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🫶 AUTHORS 🫶

• 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.

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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.

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and that's the whole page, bestie, we ate and left no crumbs 🍓💅 this one came straight from Comedi, dated 03/20/2026, and it lives at COMEDI_GET_BUFFER_WR(3) — see you in the next manpage, periodt 🌈⭐