sysvipc/sys/msg.h

   1 /* Copyright (C) 1995-2017 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    <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _SYS_MSG_H
  19 #define _SYS_MSG_H
  20
  21 #include <features.h>
  22
  23 #define __need_size_t
  24 #include <stddef.h>
  25
  26 /* Get common definition of System V style IPC.  */
  27 #include <sys/ipc.h>
  28
  29 /* Get system dependent definition of `struct msqid_ds' and more.  */
  30 #include <bits/msq.h>
  31
  32 /* Define types required by the standard.  */
  33 #include <bits/types/time_t.h>
  34
  35 #ifndef __pid_t_defined
  36 typedef __pid_t pid_t;
  37 # define __pid_t_defined
  38 #endif
  39
  40 #ifndef __ssize_t_defined
  41 typedef __ssize_t ssize_t;
  42 # define __ssize_t_defined
  43 #endif
  44
  45 /* The following System V style IPC functions implement a message queue
  46    system.  The definition is found in XPG2.  */
  47
  48 #ifdef __USE_GNU
  49 /* Template for struct to be used as argument for `msgsnd' and `msgrcv'.  */
  50 struct msgbuf
  51   {
  52     __syscall_slong_t mtype;    /* type of received/sent message */
  53     char mtext[1];              /* text of the message */
  54   };
  55 #endif
  56
  57
  58 __BEGIN_DECLS
  59
  60 /* Message queue control operation.  */
  61 extern int msgctl (int __msqid, int __cmd, struct msqid_ds *__buf) __THROW;
  62
  63 /* Get messages queue.  */
  64 extern int msgget (key_t __key, int __msgflg) __THROW;
  65
  66 /* Receive message from message queue.
  67
  68    This function is a cancellation point and therefore not marked with
  69    __THROW.  */
  70 extern ssize_t msgrcv (int __msqid, void *__msgp, size_t __msgsz,
  71                        long int __msgtyp, int __msgflg);
  72
  73 /* Send message to message queue.
  74
  75    This function is a cancellation point and therefore not marked with
  76    __THROW.  */
  77 extern int msgsnd (int __msqid, const void *__msgp, size_t __msgsz,
  78                    int __msgflg);
  79
  80 __END_DECLS
  81
  82 #endif /* sys/msg.h */