include/sys/shm.h

   1 #ifndef _SYS_SHM_H
   2 #define _SYS_SHM_H
   3
   4 #include <sys/types.h>
   5 #include <sys/ipc.h>
   6
   7 #include <unistd.h>
   8
   9 typedef unsigned long int shmatt_t;
  10
  11 #define SHMLBA  getpagesize()
  12 #define SHMMNI  4096
  13 #define SHMSEG  32              /* max shared segs per process */
  14
  15 struct shmid_ds
  16 {
  17         struct ipc_perm shm_perm;       /* Ownership and permissions */
  18         size_t  shm_segsz;                      /* Size of segment (bytes) */
  19         time_t  shm_atime;                      /* Last attach time */
  20         time_t  shm_dtime;                      /* Last detach time */
  21         time_t  shm_ctime;                      /* Last change time */
  22         pid_t   shm_cpid;                       /* PID of creator */
  23         pid_t   shm_lpid;                       /* PID of last shmat()/shmdt() */
  24         shmatt_t        shm_nattch;             /* No. of current attaches */
  25 };
  26
  27 /* Permission flag for shmget. */
  28 #define SHM_R   0400
  29 #define SHM_W   0200
  30
  31 #define SHM_RDONLY 010000               /* attach read-only else read-write */
  32 #define SHM_RND    020000               /* round attach address to SHMLBA */
  33
  34 /* shm_mode upper byte flags */
  35 #define SHM_DEST 01000                  /* segment will be destroyed on last detach */
  36 #define SHM_LOCKED 02000                /* segment will not be swapped */
  37
  38 /* ipcs ctl commands */
  39 #define SHM_STAT        13
  40 #define SHM_INFO        14
  41
  42 struct  shminfo
  43 {
  44         unsigned long int shmmax;
  45         unsigned long int shmmin;
  46         unsigned long int shmmni;
  47         unsigned long int shmseg;
  48         unsigned long int shmall;
  49 };
  50
  51 struct shm_info
  52 {
  53         int used_ids;
  54         unsigned long int shm_tot;  /* total allocated shm */
  55         unsigned long int shm_rss;  /* total resident shm */
  56         unsigned long int shm_swp;  /* total swapped shm */
  57         unsigned long int swap_attempts;
  58         unsigned long int swap_successes;
  59 };
  60
  61 /* The following System V style IPC functions implement a shared memory
  62  * facility.  The definition is found in XPG4.2.
  63  */
  64
  65 /* Shared memory control operation. */
  66 _PROTOTYPE( int shmctl, (int __shmid, int __cmd, struct shmid_ds *__buf));
  67
  68 /* Get shared memory segment. */
  69 _PROTOTYPE( int shmget, (key_t __key, size_t __size, int __shmflg));
  70
  71 /* Attach shared memory segment. */
  72 _PROTOTYPE( void *shmat, (int __shmid, const void *__shmaddr, int __shmflg));
  73
  74 /* Deattach shared memory segment. */
  75 _PROTOTYPE( int shmdt, (const void *__shmaddr));
  76
  77 #endif /* _SYS_SHM_H */