shm.h

/* Copyright (C) 1995-2016 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#ifndef _SYS_SHM_H
# error "Never include <bits/shm.h> directly; use <sys/shm.h> instead."
#endif

#include <bits/types.h>

/* Flags for `shmat'.  */
#define SHM_RDONLY	010000		/* attach read-only else read-write */
#define SHM_RND		020000		/* round attach address to SHMLBA */
#define SHM_REMAP	040000		/* take-over region on attach */

/* Commands for `shmctl'.  */
#define SHM_LOCK	11		/* lock segment (root only) */
#define SHM_UNLOCK	12		/* unlock segment (root only) */

__BEGIN_DECLS

/* Segment low boundary address multiple.  */
#define SHMLBA		(__getpagesize ())
extern int __getpagesize (void) __THROW __attribute__ ((__const__));


/* Type to count number of attaches.  */
typedef unsigned short int shmatt_t;

/* Data structure describing a shared memory segment.  */
struct shmid_ds
  {
    struct ipc_perm shm_perm;		/* operation permission struct */
    int shm_segsz;			/* size of segment in bytes */
    __time_t shm_atime;			/* time of last shmat() */
    __time_t shm_dtime;			/* time of last shmdt() */
    __time_t shm_ctime;			/* time of last change by shmctl() */
    __pid_t shm_cpid;			/* pid of creator */
    __pid_t shm_lpid;			/* pid of last shmop */
    shmatt_t shm_nattch;		/* number of current attaches */
  };

__END_DECLS