rt/mqueue.h

   1 /* Copyright (C) 2004-2019 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _MQUEUE_H
  19 #define _MQUEUE_H       1
  20
  21 #include <features.h>
  22 #include <sys/types.h>
  23 #include <fcntl.h>
  24 #include <bits/types/sigevent_t.h>
  25 #include <bits/types/struct_timespec.h>
  26 /* Get the definition of mqd_t and struct mq_attr.  */
  27 #include <bits/mqueue.h>
  28
  29 __BEGIN_DECLS
  30
  31 /* Establish connection between a process and a message queue NAME and
  32    return message queue descriptor or (mqd_t) -1 on error.  OFLAG determines
  33    the type of access used.  If O_CREAT is on OFLAG, the third argument is
  34    taken as a `mode_t', the mode of the created message queue, and the fourth
  35    argument is taken as `struct mq_attr *', pointer to message queue
  36    attributes.  If the fourth argument is NULL, default attributes are
  37    used.  */
  38 extern mqd_t mq_open (const char *__name, int __oflag, ...)
  39   __THROW __nonnull ((1));
  40
  41 /* Removes the association between message queue descriptor MQDES and its
  42    message queue.  */
  43 extern int mq_close (mqd_t __mqdes) __THROW;
  44
  45 /* Query status and attributes of message queue MQDES.  */
  46 extern int mq_getattr (mqd_t __mqdes, struct mq_attr *__mqstat)
  47   __THROW __nonnull ((2));
  48
  49 /* Set attributes associated with message queue MQDES and if OMQSTAT is
  50    not NULL also query its old attributes.  */
  51 extern int mq_setattr (mqd_t __mqdes,
  52                        const struct mq_attr *__restrict __mqstat,
  53                        struct mq_attr *__restrict __omqstat)
  54   __THROW __nonnull ((2));
  55
  56 /* Remove message queue named NAME.  */
  57 extern int mq_unlink (const char *__name) __THROW __nonnull ((1));
  58
  59 /* Register notification issued upon message arrival to an empty
  60    message queue MQDES.  */
  61 extern int mq_notify (mqd_t __mqdes, const struct sigevent *__notification)
  62      __THROW;
  63
  64 /* Receive the oldest from highest priority messages in message queue
  65    MQDES.  */
  66 extern ssize_t mq_receive (mqd_t __mqdes, char *__msg_ptr, size_t __msg_len,
  67                            unsigned int *__msg_prio) __nonnull ((2));
  68
  69 /* Add message pointed by MSG_PTR to message queue MQDES.  */
  70 extern int mq_send (mqd_t __mqdes, const char *__msg_ptr, size_t __msg_len,
  71                     unsigned int __msg_prio) __nonnull ((2));
  72
  73 #ifdef __USE_XOPEN2K
  74 /* Receive the oldest from highest priority messages in message queue
  75    MQDES, stop waiting if ABS_TIMEOUT expires.  */
  76 extern ssize_t mq_timedreceive (mqd_t __mqdes, char *__restrict __msg_ptr,
  77                                 size_t __msg_len,
  78                                 unsigned int *__restrict __msg_prio,
  79                                 const struct timespec *__restrict __abs_timeout)
  80   __nonnull ((2, 5));
  81
  82 /* Add message pointed by MSG_PTR to message queue MQDES, stop blocking
  83    on full message queue if ABS_TIMEOUT expires.  */
  84 extern int mq_timedsend (mqd_t __mqdes, const char *__msg_ptr,
  85                          size_t __msg_len, unsigned int __msg_prio,
  86                          const struct timespec *__abs_timeout)
  87   __nonnull ((2, 5));
  88 #endif
  89
  90 /* Define some inlines helping to catch common problems.  */
  91 #if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function \
  92     && defined __va_arg_pack_len
  93 # include <bits/mqueue2.h>
  94 #endif
  95
  96 __END_DECLS
  97
  98 #endif /* mqueue.h */