msgqueue.h File Reference

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Macros
#define	MSG_PRIORITY   1
	Indicates a message as important. More...
#define	MSG_NOBLOCK   2
	TODO. More...

Functions
int	send_message (int qid, int type, char *msg, int len, short flag)
int	receive_message (int qid, int type, char **msg)
int	remove_queue (int qid)
int	create_queue (void)

Macro Definition Documentation

MSG_NOBLOCK

#define MSG_NOBLOCK   2

TODO.

Definition at line 6 of file msgqueue.h.

MSG_PRIORITY

#define MSG_PRIORITY   1

Indicates a message as important.

Even when the queue is full, there is some space left for important messages.

Definition at line 5 of file msgqueue.h.

Function Documentation

create_queue()

int create_queue

(

void

)

Create a new message queue.

Returns

A new message queue identifier.

Definition at line 116 of file msgqueue.c.

receive_message()

int receive_message	(	int	qid,
		int	type,
		char **	msg
	)

Receive a message from a message queue.

Parameters

[in]	qid	The message queue to send the message to.
[in]	type	Type of message, must be > 0.
[in,out]	msg	NULL pointer, afterwards this points to the received message.

Returns

Size of message, or -1 on error.

Definition at line 86 of file msgqueue.c.

remove_queue()

int remove_queue

(

int

qid

)

Destroy a message queue.

Parameters

[in]

qid

The message queue to destroy.

Returns

return value

• 0 succeed
• -1 failed

Definition at line 106 of file msgqueue.c.

send_message()

int send_message	(	int	qid,
		int	type,
		char *	msg,
		int	len,
		short	flag
	)

function to call to send a message

Parameters

[in]	qid	The message queue to send the message to.
[in]	type	Type of message, must be > 0.
[in]	msg	Pointer to a string containing the actual text (terminating character is not required).
[in]	len	Number of characters to copy from 'msg' to the message queue (when 'len' == 0 it copy up to the first '\0' character).
[in]	flag	Set to MSG_PRIORITY to indicate this as important message, otherwise use 0.

Returns

return values:

• 0 succeed
• -1 message too big
• -2 message queue does not exist
• -3 message queue full
• -4 other error, check errno for more details

Definition at line 24 of file msgqueue.c.