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[glibc/history.git] / bits / shm.h
blobdf7694902475efda7923c465ebd7b44d64cce991
1 /* Copyright (C) 1995, 1996, 1997, 2000, 2002, 2004
2 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
20 #ifndef _SYS_SHM_H
21 # error "Never include <bits/shm.h> directly; use <sys/shm.h> instead."
22 #endif
24 #include <bits/types.h>
26 /* Flags for `shmat'. */
27 #define SHM_RDONLY 010000 /* attach read-only else read-write */
28 #define SHM_RND 020000 /* round attach address to SHMLBA */
29 #define SHM_REMAP 040000 /* take-over region on attach */
31 /* Commands for `shmctl'. */
32 #define SHM_LOCK 11 /* lock segment (root only) */
33 #define SHM_UNLOCK 12 /* unlock segment (root only) */
35 __BEGIN_DECLS
37 /* Segment low boundary address multiple. */
38 #define SHMLBA (__getpagesize ())
39 extern int __getpagesize (void) __THROW __attribute__ ((__const__));
42 /* Type to count number of attaches. */
43 typedef unsigned short int shmatt_t;
45 /* Data structure describing a shared memory segment. */
46 struct shmid_ds
48 struct ipc_perm shm_perm; /* operation permission struct */
49 int shm_segsz; /* size of segment in bytes */
50 __time_t shm_atime; /* time of last shmat() */
51 __time_t shm_dtime; /* time of last shmdt() */
52 __time_t shm_ctime; /* time of last change by shmctl() */
53 __pid_t shm_cpid; /* pid of creator */
54 __pid_t shm_lpid; /* pid of last shmop */
55 shmatt_t shm_nattch; /* number of current attaches */
58 __END_DECLS