Message Queues

Message Queue Support. More...

Collaboration diagram for Message Queues:

Functions
NUTMSGQ *	NutMsgQCreate (uint8_t bits)
	Allocate a new message que.
int	NutMsgQBroadcast (uint8_t id, int param, void *data)
	Send a message to all message ques.
int	NutMsgQPost (NUTMSGQ *que, uint8_t id, int param, void *data)
	Send a message to a que and return immediately.
int	NutMsgQSend (NUTMSGQ *que, uint8_t id, int param, void *data)
	Send a message to a que and yields so that a waiting thread can act on the message.
int	NutMsgQFull (NUTMSGQ *que)
	Checks the state of a que.
HANDLE	NutMsgQStartTimer (NUTMSGQ *que, uint32_t ms, int param, void *data, uint8_t flags)
	Starts a periodic or one-shot timer on the given que.
void	NutMsgQStopTimer (HANDLE timer)
	Stops a timer.
int	NutMsgQGetMessage (NUTMSGQ *que, NUTMSG *msg, uint32_t timeout)
	Gets the next message from the que.
void	NutMsgQFlush (NUTMSGQ *que)
	Removes all entries from a que.
Variables
NUTMSGQ *	nutMsgQue
	global list of ques
NUTMSGTMR *	nutMsgFreeTimers

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Detailed Description

Message Queue Support.

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Function Documentation

NUTMSGQ* NutMsgQCreate

(

uint8_t

bits

)

Allocate a new message que.

Parameters:

bits	size of the que in bits

Returns:

Handle of the new que

Note:

que size will be 2^bits

References ASSERT, _NUTMSGQ::mq_mask, _NUTMSGQ::mq_next, NutHeapAllocClear, and nutMsgQue.

int NutMsgQBroadcast	(	uint8_t	id,
		int	param,
		void *	data
	)

Send a message to all message ques.

Parameters:

id	the id of the sent message
param	the param of the sent message
data	the data of the sent message

Returns:

0 if sent to all ques, < 0 if one or more ques were full

References _NUTMSGQ::mq_next, NutMsgQPost(), and nutMsgQue.

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int NutMsgQPost	(	NUTMSGQ *	que,
		uint8_t	id,
		int	param,
		void *	data
	)

Send a message to a que and return immediately.

Parameters:

que	the que to send to
id	the id of the sent message
param	the param of the sent message
data	the data of the sent message

Returns:

0 if sent, < 0 if the que is full

References _NUTMSG::data, _NUTMSG::id, _NUTMSGQ::mq_mask, _NUTMSGQ::mq_que, _NUTMSGQ::mq_wait, _NUTMSGQ::mq_write, NutEnterCritical, NutEventPostAsync(), NutExitCritical, NutJumpOutCritical, NutMsgQFull(), and _NUTMSG::param.

Referenced by NutMsgQBroadcast(), and NutMsgQSend().

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int NutMsgQSend	(	NUTMSGQ *	que,
		uint8_t	id,
		int	param,
		void *	data
	)

Send a message to a que and yields so that a waiting thread can act on the message.

The sending thread should have a lower priority than the receiver thread

Parameters:

que	the que to send to
id	the id of the sent message
param	the param of the sent message
data	the data of the sent message

Returns:

0 if sent, < 0 if the que is full

References NutMsgQPost(), and NutThreadYield().

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int NutMsgQFull

(

NUTMSGQ *

que

)

Checks the state of a que.

Returns:

-1 if full

References _NUTMSGQ::mq_mask, _NUTMSGQ::mq_read, and _NUTMSGQ::mq_write.

Referenced by NutMsgQPost().

HANDLE NutMsgQStartTimer	(	NUTMSGQ *	que,
		uint32_t	ms,
		int	param,
		void *	data,
		uint8_t	flags
	)

Starts a periodic or one-shot timer on the given que.

Parameters:

que	the que to send to
ms	timeout length of the timer
param	the param of the sent message
data	the data of the sent message
flags	0 or TM_ONESHOT

Returns:

HANDLE of the new timer

References ASSERT, _NUTMSGQ::mq_timers, _NUTMSGTMR::mt_data, _NUTMSGTMR::mt_flags, _NUTMSGTMR::mt_handle, _NUTMSGTMR::mt_next, _NUTMSGTMR::mt_param, _NUTMSGTMR::mt_que, NULL, NutHeapAlloc, nutMsgFreeTimers, NutTimerStart(), and TM_ONESHOT.

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void NutMsgQStopTimer

(

HANDLE

timer

)

Stops a timer.

Parameters:

timer

HANDLE of the timer to stop

Note:

You must not stop a one shot that has already expired otherwise it *could* have been reused and you will end up stopping another timer

References _NUTMSG::data, _NUTMSG::id, _NUTMSGQ::mq_mask, _NUTMSGQ::mq_que, _NUTMSGQ::mq_read, _NUTMSGQ::mq_write, MSG_NULL, MSG_TIMER, _NUTMSGTMR::mt_handle, _NUTMSGTMR::mt_que, NutEnterCritical, NutExitCritical, and NutTimerStop().

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int NutMsgQGetMessage	(	NUTMSGQ *	que,
		NUTMSG *	msg,
		uint32_t	timeout
	)

Gets the next message from the que.

Parameters:

que	the que to wait on
msg	pointer to memory to return data to
timeout	how long to wait for a message

Returns:

-1 on timeout, 0 if message retreived

References ASSERT, _NUTMSG::data, _NUTMSG::id, _NUTMSGQ::mq_mask, _NUTMSGQ::mq_que, _NUTMSGQ::mq_read, _NUTMSGQ::mq_wait, _NUTMSGQ::mq_write, MSG_TIMER, _NUTMSGTMR::mt_data, _NUTMSGTMR::mt_flags, _NUTMSGTMR::mt_param, NutEnterCritical, NutEventPostAsync(), NutEventWait(), NutExitCritical, NutJumpOutCritical, _NUTMSG::param, and TM_ONESHOT.

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void NutMsgQFlush

(

NUTMSGQ *

que

)

Removes all entries from a que.

References _NUTMSGQ::mq_read, _NUTMSGQ::mq_wait, _NUTMSGQ::mq_write, NutEnterCritical, and NutExitCritical.

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Variable Documentation

NUTMSGQ* nutMsgQue

global list of ques

Referenced by NutMsgQBroadcast(), and NutMsgQCreate().

NUTMSGTMR* nutMsgFreeTimers

Referenced by NutMsgQStartTimer().