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, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _SYS_SHM_H
  20 # error "Never include <bits/shm.h> directly; use <sys/shm.h> instead."
  21 #endif
  22
  23 #include <bits/types.h>
  24
  25 /* Flags for `shmat'.  */
  26 #define SHM_RDONLY      010000          /* attach read-only else read-write */
  27 #define SHM_RND         020000          /* round attach address to SHMLBA */
  28 #define SHM_REMAP       040000          /* take-over region on attach */
  29
  30 /* Commands for `shmctl'.  */
  31 #define SHM_LOCK        11              /* lock segment (root only) */
  32 #define SHM_UNLOCK      12              /* unlock segment (root only) */
  33
  34 __BEGIN_DECLS
  35
  36 /* Segment low boundary address multiple.  */
  37 #define SHMLBA          (__getpagesize ())
  38 extern int __getpagesize (void) __THROW __attribute__ ((__const__));
  39
  40
  41 /* Type to count number of attaches.  */
  42 typedef unsigned short int shmatt_t;
  43
  44 /* Data structure describing a shared memory segment.  */
  45 struct shmid_ds
  46   {
  47     struct ipc_perm shm_perm;           /* operation permission struct */
  48     int shm_segsz;                      /* size of segment in bytes */
  49     __time_t shm_atime;                 /* time of last shmat() */
  50     __time_t shm_dtime;                 /* time of last shmdt() */
  51     __time_t shm_ctime;                 /* time of last change by shmctl() */
  52     __pid_t shm_cpid;                   /* pid of creator */
  53     __pid_t shm_lpid;                   /* pid of last shmop */
  54     shmatt_t shm_nattch;                /* number of current attaches */
  55   };
  56
  57 __END_DECLS