Back to index

glibc  2.9
shm.h
Go to the documentation of this file.
00001 /* Copyright (C) 1995, 1996, 1997, 2000, 2002, 2004
00002    Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #ifndef _SYS_SHM_H
00021 # error "Never include <bits/shm.h> directly; use <sys/shm.h> instead."
00022 #endif
00023 
00024 #include <bits/types.h>
00025 
00026 /* Flags for `shmat'.  */
00027 #define SHM_RDONLY   010000        /* attach read-only else read-write */
00028 #define SHM_RND             020000        /* round attach address to SHMLBA */
00029 #define SHM_REMAP    040000        /* take-over region on attach */
00030 
00031 /* Commands for `shmctl'.  */
00032 #define SHM_LOCK     11            /* lock segment (root only) */
00033 #define SHM_UNLOCK   12            /* unlock segment (root only) */
00034 
00035 __BEGIN_DECLS
00036 
00037 /* Segment low boundary address multiple.  */
00038 #define SHMLBA              (__getpagesize ())
00039 extern int __getpagesize (void) __THROW __attribute__ ((__const__));
00040 
00041 
00042 /* Type to count number of attaches.  */
00043 typedef unsigned short int shmatt_t;
00044 
00045 /* Data structure describing a shared memory segment.  */
00046 struct shmid_ds
00047   {
00048     struct ipc_perm shm_perm;             /* operation permission struct */
00049     int shm_segsz;                 /* size of segment in bytes */
00050     __time_t shm_atime;                   /* time of last shmat() */
00051     __time_t shm_dtime;                   /* time of last shmdt() */
00052     __time_t shm_ctime;                   /* time of last change by shmctl() */
00053     __pid_t shm_cpid;                     /* pid of creator */
00054     __pid_t shm_lpid;                     /* pid of last shmop */
00055     shmatt_t shm_nattch;           /* number of current attaches */
00056   };
00057 
00058 __END_DECLS