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Notes: @(#)shm.h 13.4 (RC International) 91/10/09 */
Names: »shm.h«
└─⟦50656ff4a⟧ Bits:30010538 TX 3.1 Coldstart
└─⟦bbf173f5c⟧ »0004«
└─⟦this⟧ »./usr/include/sys/shm.h«
/* @(#)shm.h 13.4 (RC International) 91/10/09 */
#ifndef _SHM_H
#define _SHM_H
/* IPC Shared Memory Facility */
#include <rc/param.h>
/* Implementation Constants */
#define SHMLBA CLBYTES /* segment low boundary address multiple */
/* Permission Definitions */
#define SHM_R 0400 /* read permission */
#define SHM_W 0200 /* write permission */
/* ipc_perm Mode Definitions */
#define SHM_SEMA 04000 /* Special semaphore memory requested */
/* Message Operation Flags */
#define SHM_RDONLY 010000 /* attach read-only (else read-write) */
#define SHM_RND 020000 /* round attach address to SHMBLA */
/*
* Structure Definitions
*/
/*
* The shared memory id data structure-
* There is on of these for every possible shared memory segment
* in the system.
*/
struct shmid_ds /* shared memory data structure */
{
struct ipc_perm shm_perm; /* operation permission struct
* MUST BE FIRST -- GROT XXXX */
pid_t shm_cpid; /* creator pid */
pid_t shm_lpid; /* pid of last operation */
time_t shm_atime; /* last attach time */
time_t shm_dtime; /* last detach time */
time_t shm_ctime; /* last change time */
/* Times measured in secs since */
/* 00:00:00 GMT, Jan. 1, 1970 */
int shm_segsz; /* size of segment (bytes) */
u_short shm_nattch; /* number of attaches */
};
/* Define shared memory limits structure */
struct shminfo
{
int shmmax; /* max shared memory segment size */
int shmmin; /* min shared memory segment size */
int shmmni; /* # of shared memory identifiers */
int shmseg; /* max attached shared memory segments per process */
/* NOTE: must not exceed U_MAXSHM in user.h */
int shmbrk; /* gap (in clicks) used between data and shared memory */
};
/* Shared memory accounting structure */
struct shmstat
{
int shmsegtot; /* total # shm segments in use */
int shmswpo; /* # of shm segment swap outs */
int shmswpi; /* # of shm segment swap ins */
};
/*
* The following manifest constants define the parameters
* for the ipc shared memory subsystem
*/
#define SHMMAX 1024*NBPG /* max shared memory seg size (bytes) =4Mb */
#define SHMMIN 4 /* min shared memory seg size (bytes) */
#define SHMMNI 30 /* max # shared memory segs system wide */
#define SHMSEG 16 /* max # attached shared memory segs/proc */
/* SHMSEG MUST NOT EXCEED U_MAXSHM in user.h */
#define SHMBRK 8192*CLSIZE /* default # pages between end of ds
* and start of shm region.
*/
#define SHMSTK NPTEPG*CLSIZE /* # pages between end of shm region and
* top of ss, to prevent sharing of page
* table pages between stack and shm region.
*/
#if defined(__STDC__)
extern int shmctl(int, int, ...);
extern int shmget(key_t, int, int);
extern char *shmat(int, void *, int);
extern int shmdt(void *);
#else /* Not __STDC__ */
extern int shmctl(), shmdt(), shmget();
extern char *shmat();
#endif /* __STDC__ */
#endif /* _SHM_H */