ipc.h

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#ifndef _LINUX_IPC_H
#define _LINUX_IPC_H
#include <linux/types.h>

typedef int key_t;              ///< should go in <types.h> type for IPC key 
#define IPC_PRIVATE ((key_t) 0)  

struct ipc_perm
{
  key_t  key;
  ushort uid;   ///< owner euid and egid 
  ushort gid;
  ushort cuid;  ///< creator euid and egid 
  ushort cgid;
  ushort mode;  ///< access modes see mode flags below 
  ushort seq;   ///< sequence number 
};


/// resource get request flags 
#define IPC_CREAT  00001000   ///< create if key is nonexistent 
#define IPC_EXCL   00002000   ///< fail if key exists 
#define IPC_NOWAIT 00004000   ///< return error on wait 


/**
*
 
 * Control commands used with semctl, msgctl and shmctl 
 * see also specific commands in sem.h, msg.h and shm.h


*/
#define IPC_RMID 0     ///< remove resource 
#define IPC_SET  1     ///< set ipc_perm options 
#define IPC_STAT 2     ///< get ipc_perm options 
#define IPC_INFO 3     ///< see ipcs 

#ifdef __KERNEL__

/// special shmsegs[id], msgque[id] or semary[id]  values 
#define IPC_UNUSED      ((void *) -1)
#define IPC_NOID        ((void *) -2)           ///< being allocated/destroyed 

/**
*
 
 * These are used to wrap system calls. See ipc/util.c, libipc.c 


*/
struct ipc_kludge {
    struct msgbuf *msgp;
    long msgtyp;
};

#define SEMOP           1
#define SEMGET          2
#define SEMCTL          3
#define MSGSND          11
#define MSGRCV          12
#define MSGGET          13
#define MSGCTL          14
#define SHMAT           21
#define SHMDT           22
#define SHMGET          23
#define SHMCTL          24

#endif // __KERNEL__ 

#endif // _LINUX_IPC_H 

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