bits/shm.h

   1 /* Copyright (C) 1995, 1996, 1997, 2000, 2002, 2004
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   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.
   9
  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.
  14
  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.  */
  19
  20 #ifndef _SYS_SHM_H
  21 # error "Never include <bits/shm.h> directly; use <sys/shm.h> instead."
  22 #endif
  23
  24 #include <bits/types.h>
  25
  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 */
  30
  31 /* Commands for `shmctl'.  */
  32 #define SHM_LOCK        11              /* lock segment (root only) */
  33 #define SHM_UNLOCK      12              /* unlock segment (root only) */
  34
  35 __BEGIN_DECLS
  36
  37 /* Segment low boundary address multiple.  */
  38 #define SHMLBA          (__getpagesize ())
  39 extern int __getpagesize (void) __THROW __attribute__ ((__const__));
  40
  41
  42 /* Type to count number of attaches.  */
  43 typedef unsigned short int shmatt_t;
  44
  45 /* Data structure describing a shared memory segment.  */
  46 struct shmid_ds
  47   {
  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 */
  56   };
  57
  58 __END_DECLS