#ifndef _UAPI_LINUX_MSG_H
  #define _UAPI_LINUX_MSG_H
  
  #include <linux/ipc.h>
  
  /* ipcs ctl commands */
  #define MSG_STAT 11
  #define MSG_INFO 12
  
  /* msgrcv options */
  #define MSG_NOERROR     010000  /* no error if message is too big */
  #define MSG_EXCEPT      020000  /* recv any msg except of specified type.*/

  #define MSG_COPY        040000  /* copy (not remove) all queue messages */

  
  /* Obsolete, used only for backwards compatibility and libc5 compiles */
  struct msqid_ds {
  	struct ipc_perm msg_perm;
  	struct msg *msg_first;		/* first message on queue,unused  */
  	struct msg *msg_last;		/* last message in queue,unused */
  	__kernel_time_t msg_stime;	/* last msgsnd time */
  	__kernel_time_t msg_rtime;	/* last msgrcv time */
  	__kernel_time_t msg_ctime;	/* last change time */
  	unsigned long  msg_lcbytes;	/* Reuse junk fields for 32 bit */
  	unsigned long  msg_lqbytes;	/* ditto */
  	unsigned short msg_cbytes;	/* current number of bytes on queue */
  	unsigned short msg_qnum;	/* number of messages in queue */
  	unsigned short msg_qbytes;	/* max number of bytes on queue */
  	__kernel_ipc_pid_t msg_lspid;	/* pid of last msgsnd */
  	__kernel_ipc_pid_t msg_lrpid;	/* last receive pid */
  };
  
  /* Include the definition of msqid64_ds */
  #include <asm/msgbuf.h>
  
  /* message buffer for msgsnd and msgrcv calls */
  struct msgbuf {

  	__kernel_long_t mtype;          /* type of message */
  	char mtext[1];                  /* message text */

  };
  
  /* buffer for msgctl calls IPC_INFO, MSG_INFO */
  struct msginfo {
  	int msgpool;
  	int msgmap; 
  	int msgmax; 
  	int msgmnb; 
  	int msgmni; 
  	int msgssz; 
  	int msgtql; 
  	unsigned short  msgseg; 
  };
  
  /*

   * MSGMNI, MSGMAX and MSGMNB are default values which can be
   * modified by sysctl.
   *
   * MSGMNI is the upper limit for the number of messages queues per
   * namespace.
   * It has been chosen to be as large possible without facilitating
   * scenarios where userspace causes overflows when adjusting the limits via
   * operations of the form retrieve current limit; add X; update limit".
   *
   * MSGMNB is the default size of a new message queue. Non-root tasks can
   * decrease the size with msgctl(IPC_SET), root tasks
   * (actually: CAP_SYS_RESOURCE) can both increase and decrease the queue
   * size. The optimal value is application dependent.
   * 16384 is used because it was always used (since 0.99.10)
   *
   * MAXMAX is the maximum size of an individual message, it's a global
   * (per-namespace) limit that applies for all message queues.
   * It's set to 1/2 of MSGMNB, to ensure that at least two messages fit into
   * the queue. This is also an arbitrary choice (since 2.6.0).

   */

  #define MSGMNI 32000   /* <= IPCMNI */     /* max # of msg queue identifiers */

  #define MSGMAX  8192   /* <= INT_MAX */   /* max size of message (bytes) */
  #define MSGMNB 16384   /* <= INT_MAX */   /* default max size of a message queue */
  
  /* unused */
  #define MSGPOOL (MSGMNI * MSGMNB / 1024) /* size in kbytes of message pool */
  #define MSGTQL  MSGMNB            /* number of system message headers */
  #define MSGMAP  MSGMNB            /* number of entries in message map */
  #define MSGSSZ  16                /* message segment size */
  #define __MSGSEG ((MSGPOOL * 1024) / MSGSSZ) /* max no. of segments */
  #define MSGSEG (__MSGSEG <= 0xffff ? __MSGSEG : 0xffff)
  
  
  #endif /* _UAPI_LINUX_MSG_H */