NAME

       comedi_mark_buffer_written - streaming buffer control

SYNOPSIS

       #include <comedilib.h>

       int comedi_mark_buffer_written(comedi_t * device, unsigned int subdevice, unsigned int num_bytes);

DESCRIPTION

       The function comedi_mark_buffer_written is used on a subdevice that has a Comedi output command in
       progress. It should only be used if you are using a mmap mapping to write data to Comedi's buffer (as
       opposed to calling write on the device file descriptor), since Comedi will automatically keep track of
       how many bytes have been transferred via write calls. This function is used to indicate that the next
       num_bytes bytes in the buffer are valid and may be sent to the device.

RETURN VALUE

       On success, comedi_mark_buffer_written returns the number of bytes successfully marked as written. The
       return value may be less than the num_bytes. On failure, -1 is returned.

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.

Comedi                                             03/31/2024                            COMEDI_MARK_BUFFER_W(3)