Queues

Pipeline-level threading element. More...

Files
file	mpipe_queue.h
	Queue element for pipeline-level threading.

Data Structures
struct	mpipe_queue
	Queue Element Structure. More...

Enumerations
enum	{ MPIPE_PROP_BASE_QUEUE_SIZE = MPIPE_PROP_TRANSFORM_LAST , MPIPE_PROP_BASE_QUEUE_THREAD_PRIORITY , MPIPE_PROP_BASE_QUEUE_LEAK }
	Queue Property Identifiers. More...
enum	mpipe_base_queue_leak { MPIPE_BASE_QUEUE_LEAK_NONE = 0 , MPIPE_BASE_QUEUE_LEAK_OLDEST , MPIPE_BASE_QUEUE_LEAK_NEWEST }
	What a full queue does with a new buffer. More...

Functions
int	mpipe_queue_init (struct mpipe_queue *queue, uint8_t id)
	Initialize a queue element.

Detailed Description

Pipeline-level threading element.

Enumeration Type Documentation

anonymous enum

anonymous enum

#include <mpipe_queue.h>

Queue Property Identifiers.

Enumerator
MPIPE_PROP_BASE_QUEUE_SIZE	Number of buffers the queue can hold.
MPIPE_PROP_BASE_QUEUE_THREAD_PRIORITY	Scheduling priority of the queue's thread.
MPIPE_PROP_BASE_QUEUE_LEAK	What a full queue does with a new buffer, an mpipe_base_queue_leak.

mpipe_base_queue_leak

enum mpipe_base_queue_leak

#include <mpipe_queue.h>

What a full queue does with a new buffer.

A queue is first a thread boundary that loses nothing, so by default a full queue holds the producer until the consumer frees a slot. A live source feeding a slower branch would rather drop: a leak policy bounds the latency instead of the producer. End of stream is never dropped.

Enumerator
MPIPE_BASE_QUEUE_LEAK_NONE	Block the producer until a slot is free.
MPIPE_BASE_QUEUE_LEAK_OLDEST	Drop the oldest queued buffer: the consumer always gets the freshest.
MPIPE_BASE_QUEUE_LEAK_NEWEST	Drop the arriving buffer: the queued ones are delivered in order.

Function Documentation

mpipe_queue_init()

int mpipe_queue_init	(	struct mpipe_queue *	queue,
		uint8_t	id )

#include <mpipe_queue.h>

Initialize a queue element.

Parameters

queue	Pointer to the element to initialize.
id	Unique element identifier.

Returns

0 on success, negative errno otherwise.