linux/include/linux/mqueue.h
<<
>>
Prefs
   1/* Copyright (C) 2003 Krzysztof Benedyczak & Michal Wronski
   2
   3   This program is free software; you can redistribute it and/or
   4   modify it under the terms of the GNU Lesser General Public
   5   License as published by the Free Software Foundation; either
   6   version 2.1 of the License, or (at your option) any later version.
   7
   8   It is distributed in the hope that it will be useful,
   9   but WITHOUT ANY WARRANTY; without even the implied warranty of
  10   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11   Lesser General Public License for more details.
  12
  13   You should have received a copy of the GNU Lesser General Public
  14   License along with this software; if not, write to the Free
  15   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  16   02111-1307 USA.  */
  17
  18#ifndef _LINUX_MQUEUE_H
  19#define _LINUX_MQUEUE_H
  20
  21#define MQ_PRIO_MAX     32768
  22/* per-uid limit of kernel memory used by mqueue, in bytes */
  23#define MQ_BYTES_MAX    819200
  24
  25struct mq_attr {
  26        long    mq_flags;       /* message queue flags                  */
  27        long    mq_maxmsg;      /* maximum number of messages           */
  28        long    mq_msgsize;     /* maximum message size                 */
  29        long    mq_curmsgs;     /* number of messages currently queued  */
  30        long    __reserved[4];  /* ignored for input, zeroed for output */
  31};
  32
  33/*
  34 * SIGEV_THREAD implementation:
  35 * SIGEV_THREAD must be implemented in user space. If SIGEV_THREAD is passed
  36 * to mq_notify, then
  37 * - sigev_signo must be the file descriptor of an AF_NETLINK socket. It's not
  38 *   necessary that the socket is bound.
  39 * - sigev_value.sival_ptr must point to a cookie that is NOTIFY_COOKIE_LEN
  40 *   bytes long.
  41 * If the notification is triggered, then the cookie is sent to the netlink
  42 * socket. The last byte of the cookie is replaced with the NOTIFY_?? codes:
  43 * NOTIFY_WOKENUP if the notification got triggered, NOTIFY_REMOVED if it was
  44 * removed, either due to a close() on the message queue fd or due to a
  45 * mq_notify() that removed the notification.
  46 */
  47#define NOTIFY_NONE     0
  48#define NOTIFY_WOKENUP  1
  49#define NOTIFY_REMOVED  2
  50
  51#define NOTIFY_COOKIE_LEN       32
  52
  53#endif
  54