COMEDI_GET_SUBDEVICE(3)

📦
version 0.11.0+5 · 7 versions
, in ubuntu resolute, ubuntu stonking

COMEDI_GET_SUBDEVICE 💅✨

okay so bestie, welcome to Comedi reference, section 3 of the manual pages 🎀 this one is all about comedi_get_subdevice_flags, and honestly? she's a baddie. let's get into it 🦋

✨ NAME ✨

comedi_get_subdevice_flags — properties of subdevice 👑

🌸 SYNOPSIS 🌸

#include <comedilib.h>

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

💖 DESCRIPTION 💖

so like, the function comedi_get_subdevice_flags returns a bitfield that describes the capabilities of the subdevice you asked about — and yes, that's the one you passed in as subdevice, belonging to the Comedi device device 💫 it's literally telling you what your subdevice can and can't do, no cap.

and if something goes wrong? the function returns -1, and the Comedilib error value gets set 😭 so like. always check, bestie. stress. 🫶

more parts coming, don't go anywhere 🌈

  • SDF_BUSY (0x00000001) — bestie the subdevice is busy rn, like it's out here mid-asynchronous-command and can't talk. ⚠️ and here's the thing: being "busy" is not the same as being "running" (that's the SDF_RUNNING state, iykyk). A "running" subdevice is always "busy", but a "busy" one is not necessarily "running". Picture it: an analog input command already got finished by the hardware, but there are still samples sitting in Comedi's buffer waiting to be read out. So in that moment the subdevice is not "running" — but it's 100% still "busy" until either all those samples get read out, or somebody calls comedi_cancel. periodt.
  • SDF_BUSY_OWNER (0x00000002) — the subdevice is "busy" and the command it's running was started by the current process. it's giving main character energy: you did this, bestie 💅
  • SDF_LOCKED (0x00000004) — this subdevice has been locked by comedi_lock. no cap.
  • SDF_LOCK_OWNER (0x00000008) — the subdevice is locked, and the current process is the one who locked it. 👑
  • SDF_MAXDATA (0x00000010) — the maximum data value for this subdevice depends on the channel.
  • SDF_FLAGS (0x00000020) — the subdevice flags depend on the channel. (note: this is unfinished/broken support in the library 🙈 fair warning.)
  • SDF_RANGETYPE (0x00000040) — the range type depends on the channel.
  • SDF_CMD (0x00001000) — slay, this subdevice supports asynchronous commands ✨
  • SDF_SOFT_CALIBRATED (0x00002000) — this subdevice relies on the host to do the calibration in software. 🧮 the software calibration coefficients are determined by the comedi_soft_calibrate utility. for the full tea, go read the description of the comedi_get_softcal_converter function.
  • SDF_READABLE (0x00010000) — the subdevice can be read (e.g. analog input).
  • SDF_WRITABLE (0x00020000) — you can write to this subdevice (e.g. analog output).
  • SDF_INTERNAL (0x00040000) — this subdevice does not have externally visible lines. it's shy. 🫣
  • SDF_GROUND (0x00100000) — the subdevice supports analog reference AREF_GROUND. 🌈
  • SDF_COMMON (0x00200000) — the subdevice supports analog reference AREF_COMMON.
  • SDF_DIFF (0x00400000) — the subdevice supports analog reference AREF_DIFF.
  • SDF_OTHER (0x00800000) — the subdevice supports analog reference AREF_OTHER. 🦋
  • SDF_DITHER — 0x01000000 — the subdevice supports dithering (via the CR_ALT_FILTER chanspec flag). ✨
  • SDF_DEGLITCH — 0x02000000 — the subdevice supports deglitching (via the CR_ALT_FILTER chanspec flag). 💅
  • SDF_RUNNING — 0x08000000 — an asynchronous command is running. You can use this flag to poll for the completion of an output command. 🔥
  • SDF_LSAMPL — 0x10000000 — the subdevice uses the 32-bit lsampl_t type instead of the 16-bit sampl_t for asynchronous command data. 🧚
  • SDF_PACKED — 0x20000000 — the subdevice uses bitfield samples for asynchronous command data, one bit per channel (otherwise it uses one sampl_t or lsampl_t per channel). Commonly used for digital subdevices. 👑

✨ AUTHORS ✨

Giving credit where it’s due, because these icons built the thing:

  • 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. 💖

Legal moment, bestie, but make it cute:

  • 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. 📬

okay bestie, that's the whole COMEDI_GET_SUBDEVICE(3) page. Source/version: Comedi, date: 03/20/2026. Stay iconic, mwah 💋✨

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