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| 2 | |
| 3 | * linux/drivers/acorn/scsi/msgqueue.h
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| 4 | *
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| 5 | * Copyright (C) 1997 Russell King
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| 6 | *
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| 7 | * message queue handling
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| 8 |
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| 9 | #ifndef MSGQUEUE_H
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| 10 | #define MSGQUEUE_H
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| 11 |
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| 12 | struct message {
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| 13 | char msg[8];
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| 14 | int length;
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| 15 | int fifo;
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| 16 | };
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| 17 |
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| 18 | struct msgqueue_entry {
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| 19 | struct message msg;
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| 20 | struct msgqueue_entry *next;
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| 21 | };
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| 22 |
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| 23 | #define NR_MESSAGES 4
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| 24 |
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| 25 | typedef struct {
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| 26 | struct msgqueue_entry *qe;
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| 27 | struct msgqueue_entry *free;
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| 28 | struct msgqueue_entry entries[NR_MESSAGES];
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| 29 | } MsgQueue_t;
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| 30 |
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| 31 | |
| 32 | * Function: void msgqueue_initialise(MsgQueue_t *msgq)
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| 33 | * Purpose : initialise a message queue
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| 34 | * Params : msgq - queue to initialise
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| 35 |
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| 36 | extern void msgqueue_initialise(MsgQueue_t *msgq);
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| 37 |
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| 38 | |
| 39 | * Function: void msgqueue_free(MsgQueue_t *msgq)
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| 40 | * Purpose : free a queue
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| 41 | * Params : msgq - queue to free
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| 42 |
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| 43 | extern void msgqueue_free(MsgQueue_t *msgq);
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| 44 |
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| 45 | |
| 46 | * Function: int msgqueue_msglength(MsgQueue_t *msgq)
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| 47 | * Purpose : calculate the total length of all messages on the message queue
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| 48 | * Params : msgq - queue to examine
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| 49 | * Returns : number of bytes of messages in queue
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| 50 |
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| 51 | extern int msgqueue_msglength(MsgQueue_t *msgq);
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| 52 |
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| 53 | |
| 54 | * Function: struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno)
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| 55 | * Purpose : return a message & its length
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| 56 | * Params : msgq - queue to obtain message from
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| 57 | * : msgno - message number
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| 58 | * Returns : pointer to message string, or NULL
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| 59 |
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| 60 | extern struct message *msgqueue_getmsg(MsgQueue_t *msgq, int msgno);
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| 61 |
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| 62 | |
| 63 | * Function: int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...)
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| 64 | * Purpose : add a message onto a message queue
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| 65 | * Params : msgq - queue to add message on
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| 66 | * length - length of message
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| 67 | * ... - message bytes
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| 68 | * Returns : != 0 if successful
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| 69 |
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| 70 | extern int msgqueue_addmsg(MsgQueue_t *msgq, int length, ...);
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| 71 |
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| 72 | |
| 73 | * Function: void msgqueue_flush(MsgQueue_t *msgq)
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| 74 | * Purpose : flush all messages from message queue
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| 75 | * Params : msgq - queue to flush
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| 76 |
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| 77 | extern void msgqueue_flush(MsgQueue_t *msgq);
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| 78 |
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| 79 | #endif
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