1/* Copyright (C) 1995-2025 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 _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
36typedef __pid_t pid_t;
37# define __pid_t_defined
38#endif
39
40#ifndef __ssize_t_defined
41typedef __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'.  */
50struct 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#ifndef __USE_TIME64_REDIRECTS
62extern int msgctl (int __msqid, int __cmd, struct msqid_ds *__buf) __THROW;
63#else
64# ifdef __REDIRECT_NTH
65extern int __REDIRECT_NTH (msgctl,
66                           (int __msqid, int __cmd, struct msqid_ds *__buf),
67                           __msgctl64);
68# else
69#  define msgctl __msgctl64
70# endif
71#endif
72
73/* Get messages queue.  */
74extern int msgget (key_t __key, int __msgflg) __THROW;
75
76/* Receive message from message queue.
77
78   This function is a cancellation point and therefore not marked with
79   __THROW.  */
80extern ssize_t msgrcv (int __msqid, void *__msgp, size_t __msgsz,
81		       long int __msgtyp, int __msgflg);
82
83/* Send message to message queue.
84
85   This function is a cancellation point and therefore not marked with
86   __THROW.  */
87extern int msgsnd (int __msqid, const void *__msgp, size_t __msgsz,
88		   int __msgflg);
89
90__END_DECLS
91
92#endif /* sys/msg.h */