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/* sys/shm.h
Copyright 2001, 2002 Red Hat Inc.
Written by Robert Collins <rbtcollins@hotmail.com>
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#ifndef _SYS_SHM_H
#define _SYS_SHM_H
#include <cygwin/ipc.h>
#ifdef __cplusplus
extern "C"
{
#endif
/* 64 Kb was hardcoded for x86. MS states this may change, but we need
* it in the header file.
*/
#define SHMLBA 65536 /* Segment low boundary address multiple. */
/* Shared memory operation flags:
*/
#define SHM_RDONLY 0x01 /* Attach read-only (else read-write). */
#define SHM_RND 0x02 /* Round attach address to SHMLBA. */
/* Command definitions for the semctl () function:
*/
#define SHM_STAT 0x4000 /* For ipcs(8) */
#define SHM_INFO 0x4001 /* For ipcs(8) */
/* Unsigned integer used for the number of current attaches.
*/
typedef unsigned int shmatt_t;
struct shmid_ds
{
struct ipc_perm shm_perm; /* Operation permission structure. */
size_t shm_segsz; /* Size of segment in bytes. */
pid_t shm_lpid; /* Process ID of last operation. */
pid_t shm_cpid; /* Process ID of creator. */
shmatt_t shm_nattch; /* Number of current attaches. */
timestruc_t shm_atim; /* Time of last shmat (). */
timestruc_t shm_dtim; /* Time of last shmdt (). */
timestruc_t shm_ctim; /* Time of last change by shmctl (). */
long shm_spare4[2];
};
#define shm_atime shm_atim.tv_sec
#define shm_dtime shm_dtim.tv_sec
#define shm_ctime shm_ctim.tv_sec
/* Buffer type for shmctl (IPC_INFO, ...) as used by ipcs(8).
*/
struct shminfo
{
unsigned long shmmax; /* Maximum size in bytes of a shared
memory segment. */
unsigned long shmmin; /* Minimum size in bytes of a shared
memory segment. */
unsigned long shmmni; /* Maximum number of shared memory
segments, system wide. */
unsigned long shmseg; /* Maximum number of shared memory
segments attached per process. */
unsigned long shmall; /* Maximum number of bytes of shared
memory, system wide. */
unsigned long shm_spare[4];
};
/* Buffer type for shmctl (SHM_INFO, ...) as used by ipcs(8).
*/
struct shm_info
{
unsigned long shm_ids; /* Number of allocated segments. */
unsigned long shm_tot; /* Size in bytes of allocated segments. */
unsigned long shm_atts; /* Number of attached segments, system
wide. */
};
void *shmat (int shmid, const void *shmaddr, int shmflg);
int shmctl (int shmid, int cmd, struct shmid_ds *buf);
int shmdt (const void *shmaddr);
int shmget (key_t key, size_t size, int shmflg);
#ifdef __cplusplus
}
#endif
#endif /* _SYS_SHM_H */
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