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/* msgQDemo.h - Header for the msgQDemo */

/* Copyright 1984-1997 Wind River Systems, Inc. */

/*
modification history
--------------------
01b,06nov97,mm added copyright.
01a,14dec93,ms written.
*/

#define CONSUMER_TASK_PRI 99 /* Priority of the consumer task */
#define PRODUCER_TASK_PRI 98 /* Priority of the producer task */
#define TASK_STACK_SIZE 5000 /* stack size for spawned tasks */

struct msg { /* data structure for msg passing */
int tid; /* task id */
int value; /* msg value */
};

LOCAL MSG_Q_ID msgQId; /* message queue id */
LOCAL int numMsg = 8; /* number of messages */
LOCAL BOOL notDone; /* Flag to indicate the completion
of this demo */

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/* msgQDemo.c - Demonstrates intertask communication using Message Queues */

/* Copyright 1984-1997 Wind River Systems, Inc. */

/*
modification history
--------------------
01c,06nov97,mm added copyright.
01b,19sep97,ram added include files stdio.h, sysLib.h
tested ok
01a,14dec93,ms written.
*/

/* includes */

#include "vxWorks.h"
#include "taskLib.h"
#include "msgQLib.h"
#include "msgQDemo.h"
#include "sysLib.h"
#include "stdio.h"

/* function prototypes */

LOCAL STATUS producerTask (); /* producer task */
LOCAL STATUS consumerTask (); /* consumer task */

/*****************************************************************************
* msgQDemo - Demonstrates intertask communication using Message Queues
*
* DESCRIPTION
* Creates a Message Queue for interTask communication between the
* producerTask and the consumerTask. Spawns the producerTask that creates
* messages and sends messages to the consumerTask using the message queue.
* Spawns the consumerTask that reads messages from the message queue.
* After consumerTask has consumed all the messages, the message queue is
* deleted.
*
* RETURNS: OK or ERROR
*
* EXAMPLE
*
* -> sp msgQDemo
*
*/

STATUS msgQDemo()
{
notDone = TRUE; /* initialize the global flag */

/* Create the message queue*/
if ((msgQId = msgQCreate (numMsg, sizeof (struct msg), MSG_Q_FIFO))
== NULL)
{
perror ("Error in creating msgQ");
return (ERROR);
}

/* Spwan the producerTask task */
if (taskSpawn ("tProducerTask", PRODUCER_TASK_PRI, 0, TASK_STACK_SIZE,
(FUNCPTR) producerTask, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
== ERROR)
{
perror ("producerTask: Error in spawning demoTask");
return (ERROR);
}

/* Spwan the consumerTask task */
if (taskSpawn ("tConsumerTask", CONSUMER_TASK_PRI, 0, TASK_STACK_SIZE,
(FUNCPTR) consumerTask, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
== ERROR)
{
perror ("consumerTask: Error in spawning demoTask");
return (ERROR);
}

/* polling is not recommended. But used to make this demonstration simple*/
while (notDone)
taskDelay (sysClkRateGet ());

if (msgQDelete (msgQId) == ERROR)
{
perror ("Error in deleting msgQ");
return (ERROR);
}

return (OK);
}

/*****************************************************************************
* producerTask - produces messages, and sends messages to the consumerTask
* using the message queue.
*
* RETURNS: OK or ERROR
*
*/

STATUS producerTask (void)
{
int count;
int value;
struct msg producedItem; /* producer item - produced data */

printf ("producerTask started: task id = %#x \n", taskIdSelf ());

/* Produce numMsg number of messages and send these messages */

for (count = 1; count <= numMsg; count++)
{
value = count * 10; /* produce a value */

/* Fill in the data structure for message passing */
producedItem.tid = taskIdSelf ();
producedItem.value = value;

/* Send Messages */
if ((msgQSend (msgQId, (char *) &producedItem, sizeof (producedItem),
WAIT_FOREVER, MSG_PRI_NORMAL)) == ERROR)
{
perror ("Error in sending the message");
return (ERROR);
}
else
printf ("ProducerTask: tid = %#x, produced value = %d \n",
taskIdSelf (), value);
}

return (OK);
}

/*****************************************************************************
* consumerTask - consumes all the messages from the message queue.
*
* RETURNS: OK or ERROR
*
*/

STATUS consumerTask (void)
{
int count;
struct msg consumedItem; /* consumer item - consumed data */

printf ("\n\nConsumerTask: Started - task id = %#x\n", taskIdSelf());

/* consume numMsg number of messages */
for (count = 1; count <= numMsg; count++)
{
/* Receive messages */
if ((msgQReceive (msgQId, (char *) &consumedItem,
sizeof (consumedItem), WAIT_FOREVER)) == ERROR)
{
perror ("Error in receiving the message");
return (ERROR);
}
else
printf ("ConsumerTask: Consuming msg of value %d from tid = %#x\n",
consumedItem.value, consumedItem.tid);
}

notDone = FALSE; /* set the global flag to FALSE to indicate completion*/
return (OK);
}

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