/* sys/ipc.h
   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 _CYGWIN_IPC_H
#define _CYGWIN_IPC_H

#include <sys/types.h>
#include <stdint.h>

#ifdef __cplusplus
extern "C"
{
#endif

struct ipc_perm
{
  uid_t  uid;			/* Owner's user ID. */
  gid_t  gid;			/* Owner's group ID. */
  uid_t  cuid;			/* Creator's user ID. */
  gid_t  cgid;			/* Creator's group ID. */
  mode_t mode;			/* Read/write permission. */
  key_t  key;
  unsigned short seq;
};

/* Mode bits:
 */
#define IPC_CREAT  0x0200	/* Create entry if key does not exist. */
#define IPC_EXCL   0x0400	/* Fail if key exists. */
#define IPC_NOWAIT 0x0800	/* Error if request must wait. */
#ifdef _KERNEL
#define IPC_KEY_IS_SHMID 0x1000	/* Used in shmget when called from shmat. */
#endif

/* Keys:
 */
#define IPC_PRIVATE ((key_t) 0)	/* Private key. */

/* Control commands:
 */
#define IPC_RMID 0x1000		/* Remove identifier. */
#define IPC_SET  0x1001		/* Set options. */
#define IPC_STAT 0x1002		/* Get options. */
#ifdef _KERNEL
#define IPC_INFO 0x1003		/* For ipcs(8). */
#endif

#ifdef _KERNEL
#define IPCID_TO_IX(id)         ((id) & 0xffff)
#define IPCID_TO_SEQ(id)        (((id) >> 16) & 0xffff)
#define IXSEQ_TO_IPCID(ix,perm) (((perm.seq) << 16) | (ix & 0xffff))

#define IPC_R           000400  /* read permission */
#define IPC_W           000200  /* write/alter permission */
#define IPC_M           010000  /* permission to change control info */
#endif

key_t ftok (const char *path, int id);

#ifdef __cplusplus
}
#endif

#endif /* _CYGWIN_IPC_H */
