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      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 
     25 struct mq_attr {
     26 	__kernel_long_t	mq_flags;	/* message queue flags			*/
     27 	__kernel_long_t	mq_maxmsg;	/* maximum number of messages		*/
     28 	__kernel_long_t	mq_msgsize;	/* maximum message size			*/
     29 	__kernel_long_t	mq_curmsgs;	/* number of messages currently queued	*/
     30 	__kernel_long_t	__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