1COMEDI_MARK_BUFFER_W(3) Comedi reference COMEDI_MARK_BUFFER_W(3)
2
3
4
6 comedi_mark_buffer_written - streaming buffer control
7
9 #include <comedilib.h>
10
11 int comedi_mark_buffer_written(comedi_t * device,
12 unsigned int subdevice,
13 unsigned int num_bytes);
14
16 The function comedi_mark_buffer_written is used on a subdevice that has
17 a Comedi output command in progress. It should only be used if you are
18 using a mmap mapping to write data to Comedi's buffer (as opposed to
19 calling write on the device file descriptor), since Comedi will
20 automatically keep track of how many bytes have been transferred via
21 write calls. This function is used to indicate that the next num_bytes
22 bytes in the buffer are valid and may be sent to the device.
23
25 On success, comedi_mark_buffer_written returns the number of bytes
26 successfully marked as written. The return value may be less than the
27 num_bytes. On failure, -1 is returned.
28
30 David Schleef <ds@schleef.org>
31 Author.
32
33 Frank Mori Hess <fmhess@users.sourceforge.net>
34 Author.
35
36 Herman Bruyninckx <Herman.Bruyninckx@mech.kuleuven.ac.be>
37 Author.
38
39 Bernd Porr <tech@linux-usb-daq.co.uk>
40 Author.
41
42 Ian Abbott <abbotti@mev.co.uk>
43 Author.
44
45 Éric Piel <piel@delmic.com>
46 Author.
47
49 Copyright © 1998-2003 David Schleef
50 Copyright © 2001-2003, 2005, 2008 Frank Mori Hess
51 Copyright © 2002-2003 Herman Bruyninckx
52 Copyright © 2012 Bernd Porr
53 Copyright © 2012 Ian Abbott
54 Copyright © 2012, 2015 Éric Piel
55
56 This document is part of Comedilib. In the context of this document,
57 the term "source code" as defined by the license is interpreted as the
58 XML source.
59
60 This library is free software; you can redistribute it and/or modify it
61 under the terms of the GNU Lesser General Public License as published
62 by the Free Software Foundation, version 2.1 of the License.
63
64 This library is distributed in the hope that it will be useful, but
65 WITHOUT ANY WARRANTY; without even the implied warranty of
66 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
67 General Public License for more details.
68
69 You should have received a copy of the GNU Lesser General Public
70 License along with this library; if not, write to the Free Software
71 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
72 USA.
73
74
75
76
77Comedi 05/11/2017 COMEDI_MARK_BUFFER_W(3)