---
name: "comedi_dio_read"
section: "3"
platform: "linux"
package: "libcomedi-dev"
version: "0.11.0+5-1.3+b1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/comedi_dio_read"
---

# comedi\_dio\_read(3)

read single bit from digital channel

## NAME

comedi\_dio\_read - read single bit from digital channel

## SYNOPSIS

```
#include <comedilib.h>
```

**int comedi\_dio\_read(comedi\_t \*** *device***, unsigned int** *subdevice***, unsigned int** *channel***, unsigned int \*** *bit***);**

## DESCRIPTION

The function **comedi\_dio\_read** reads the channel *channel* belonging to the subdevice *subdevice* of device *device*. The data value that is read is stored in the \**bit*. This function is equivalent to:

```
comedi_data_read(device, subdevice, channel, 0, 0, bit);
```

This function does not require a digital subdevice or a subdevice with a maximum data value of 1 to work properly.

If you wish to read multiple digital channels at once, it is more efficient to use **comedi\_dio\_bitfield2** than to call this function multiple times.

## RETURN VALUE

Return values and errors are the same as **comedi\_data\_read**.

## 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.

## 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.