unix/src/hpux-7-0/Ushm.i3


Copyright (C) 1994, Digital Equipment Corp.

INTERFACE Ushm;

FROM Ctypes IMPORT int;
FROM Utypes IMPORT time_t, key_t, ushort, swblk_t;
FROM Uipc   IMPORT struct_ipc_perm;
** <sys/shm.h> **

** IPC Shared Memory Facility.

** Implementation Constants.

CONST
                        (* segment low boundary address multiple *)
                        (* (SMLBA must be a power of 2) *)
  (* SMLBA = ctob(CLSIZE);   where does ctob come from ? - em *)
  NSHMDAD = 12;
                        (* for SYSTEM V compatibility           *)
  (* SHMLBA = SMLBA;         see SMLBA - em *)

** Permission Definitions.

SM_R = 8_0400; (* read permission *)
  SM_W = 8_0200;  (* write permission *)

                        (* for SYSTEM V compatibility           *)
  SHM_R = SM_R;
  SHM_W = SM_W;

** ipc_perm Mode Definitions.

SM_CLEAR = 8_01000; (* clear segment on next attach *)
  SM_DEST  = 8_02000; (* destroy seg when # attached = 0 *)

                        (* for SYSTEM V compatibility           *)
  SHM_INIT = SM_CLEAR;
  SHM_DEST = SM_DEST;

** Message Operation Flags.

SM_RDONLY = 8_010000;        (* attach read-only (else read-write) *)
  SM_RND    = 8_020000;        (* round attach address to SHMLBA *)

                        (* for SYSTEM V compatibility           *)
  SHM_RDONLY = SM_RDONLY;
  SHM_RND    = SM_RND;

* sizing constant (the balance are in /sys/h/param.h and /sys/conf/param.c.

SMMNI = 100;        (* Max number SM segments in system *)

** Structure Definitions.

** There is a shared mem id struct for each segment in the system.

TYPE
  struct_shmid_ds = RECORD
                                (* SM_PERM must be the first    *)
                                (* element in the structure.    *)
      shm_perm:    struct_ipc_perm;          (* permission struct *)
      shm_segsz:   int;                      (* segment size (bytes) *)
      shm_ptbl:    ADDRESS;                 (* where is struct_pte ? - em *)
      shm_lpid:    ushort;                   (* pid of last smop *)
      shm_cpid:    ushort;                   (* pid of creator *)
      shm_nattch:  ushort;                     (* reference count *)
      shm_cnattch: ushort;                     (* reference count *)
      shm_atime:   time_t;                   (* last smat time *)
      shm_dtime:   time_t;                   (* last smdt time *)
      shm_ctime:   time_t;                   (* last change time *)
      shm_umptbl:  ADDRESS;
	shm_daddr: ARRAY [1..NSHMDAD] OF swblk_t;
	shm_poip:  ushort;
	shm_rssize: ushort;
	shm_flag:  int;
    END;
  struct_shmid_ds_star = UNTRACED REF struct_shmid_ds;

  struct_shmpt_ds = RECORD
	shm_dsptr: struct_shmid_ds;
	shm_spte: int;			(* starting pte entry *)
	shm_sflg: int;			(* R/W permission on segment *)
    END;

CONST
NOTE: These values must align with X* flag values in text.h
SMLOCK =  8_0010;           (* Being swapped in or out *)
  SMWANT =  8_0020;           (* Wanted for swapping *)
  SMNOSW =  8_0100;           (* Lock segment in memory *)
shared memory specific commands for shmctl syscall
SHM_LOCK   = 3;       (* Lock segment in memory *)
  SHM_UNLOCK = 4;       (* Unlock segment in memory *)

* sminfo structure is used by the system for bounds checking. All of * the elements in this structure are initialized in /sys/conf/param.c. * * Three of the elements are configurable via the config program * (smmax, smmin, smbrk). If they are not config'ed, then they all * have defaults.

TYPE
  struct_sminfo = RECORD
      smmax: int;       (* max shared memory segment size *)
      smmin: int;       (* min shared memory segment size *)
      smmni: int;       (* # of shared memory identifiers *)
      smseg: int;       (* max attached shared memory segs per proc *)
      smbrk: int;       (* gap (in clicks) used between data and SM *)
      smsmat: int;      (* max shmem attach addr (clicks) *)
    END;

                        (* for SYSTEM V compatibility *)
  struct_shminfo = RECORD
      shmmax: int;       (* max shared memory segment size *)
      shmmin: int;       (* min shared memory segment size *)
      shmmni: int;       (* # of shared memory identifiers *)
      shmseg: int;       (* max attached shared memory segs per proc *)
      shmbrk: int;       (* gap (in clicks) used between data and SM *)
      smsmall: int;       (* max shmem attach addr (clicks) *)
    END;
** shmctl(2) - shared memory control operations **

<*EXTERNAL*> PROCEDURE shmctl (shmid, cmd: int;
                               buf: UNTRACED REF struct_shmid_ds): int;
** shmget(2) - get shared memory segment **

<*EXTERNAL*> PROCEDURE shmget (key: key_t; size, semflg: int): int;
** shmat(2), shmdt(2) - shared memory operations **

<*EXTERNAL*> PROCEDURE shmat (shmid: int; shmaddr: ADDRESS; shmflg: int): int;
<*EXTERNAL*> PROCEDURE shmdt (shmaddr: ADDRESS): int;

END Ushm.

interface Utypes is in:


interface Uipc is in: