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/*
* msgqueue.h: message queue handling
*
* (c) 1997 Russell King
*/
#ifndef MSGQUEUE_H
#define MSGQUEUE_H
struct msgqueue_entry {
char msg[8];
int length;
struct msgqueue_entry *next;
};
#define NR_MESSAGES 4
typedef struct {
struct msgqueue_entry *qe;
struct msgqueue_entry *free;
struct msgqueue_entry entries[NR_MESSAGES];
} MsgQueue_t;
/*
* Function: void msgqueue_initialise (MsgQueue_t *msgq)
* Purpose : initialise a message queue
* Params : msgq - queue to initialise
*/
extern void msgqueue_initialise (MsgQueue_t *msgq);
/*
* Function: void msgqueue_free (MsgQueue_t *msgq)
* Purpose : free a queue
* Params : msgq - queue to free
*/
extern void msgqueue_free (MsgQueue_t *msgq);
/*
* Function: int msgqueue_msglength (MsgQueue_t *msgq)
* Purpose : calculate the total length of all messages on the message queue
* Params : msgq - queue to examine
* Returns : number of bytes of messages in queue
*/
extern int msgqueue_msglength (MsgQueue_t *msgq);
/*
* Function: char *msgqueue_getnextmsg (MsgQueue_t *msgq, int *length)
* Purpose : return a message & its length
* Params : msgq - queue to obtain message from
* length - pointer to int for message length
* Returns : pointer to message string, or NULL
*/
extern char *msgqueue_getnextmsg (MsgQueue_t *msgq, int *length);
/*
* Function: char *msgqueue_peeknextmsg(MsgQueue_t *msgq, int *length)
* Purpose : return next message & length without removing it from the list
* Params : msgq - queue to obtain message from
* : length - pointer to int for message length
* Returns : pointer to message string, or NULL
*/
extern char *msgqueue_peeknextmsg(MsgQueue_t *msgq, int *length);
/*
* Function: int msgqueue_addmsg (MsgQueue_t *msgq, int length, ...)
* Purpose : add a message onto a message queue
* Params : msgq - queue to add message on
* length - length of message
* ... - message bytes
* Returns : != 0 if successful
*/
extern int msgqueue_addmsg (MsgQueue_t *msgq, int length, ...);
/*
* Function: void msgqueue_flush (MsgQueue_t *msgq)
* Purpose : flush all messages from message queue
* Params : msgq - queue to flush
*/
extern void msgqueue_flush (MsgQueue_t *msgq);
#endif
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