Message Queues
[Application Candies]

Collaboration diagram for Message Queues:

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Detailed Description

Message Queue Support.

Functions
NUTMSGQ *	NutMsgQCreate (u_char bits)
	Allocate a new message que.
int	NutMsgQBroadcast (u_char id, int param, void *data)
	Send a message to all message ques.
int	NutMsgQPost (NUTMSGQ *que, u_char id, int param, void *data)
	Send a message to a que and return immediately.
int	NutMsgQSend (NUTMSGQ *que, u_char 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, u_long ms, int param, void *data, u_char 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, u_long 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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Function Documentation

NUTMSGQ* NutMsgQCreate (  u_char  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

int NutMsgQBroadcast (  u_char  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

int NutMsgQPost (  NUTMSGQ *  que, u_char  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

int NutMsgQSend (  NUTMSGQ *  que, u_char  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

int NutMsgQFull (  NUTMSGQ *  que  )

Checks the state of a que. Returns: -1 if full

HANDLE NutMsgQStartTimer (  NUTMSGQ *  que, u_long  ms, int  param, void *  data, u_char  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

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

int NutMsgQGetMessage (  NUTMSGQ *  que, NUTMSG *  msg, u_long  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

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