pmutil.h File Reference

lock-free queue for building MIDI applications with PortMidi. More...

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Typedefs
typedef void	PmQueue
	The queue representation is opaque. More...

Functions
PMEXPORT PmQueue *	Pm_QueueCreate (long num_msgs, int32_t bytes_per_msg)
	create a single-reader, single-writer queue. More...
PMEXPORT PmError	Pm_QueueDestroy (PmQueue *queue)
	destroy a queue and free its storage. More...
PMEXPORT PmError	Pm_Dequeue (PmQueue *queue, void *msg)
	remove one message from the queue, copying it into msg. More...
PMEXPORT PmError	Pm_Enqueue (PmQueue *queue, void *msg)
	insert one message into the queue, copying it from msg. More...
PMEXPORT int	Pm_QueueFull (PmQueue *queue)
	test if the queue is full. More...
PMEXPORT int	Pm_QueueEmpty (PmQueue *queue)
	test if the queue is empty. More...
PMEXPORT void *	Pm_QueuePeek (PmQueue *queue)
	get a pointer to the item at the head of the queue. More...
PMEXPORT PmError	Pm_SetOverflow (PmQueue *queue)
	allows the writer (enqueuer) to signal an overflow condition to the reader (dequeuer). More...

Detailed Description

lock-free queue for building MIDI applications with PortMidi.

PortMidi is not reentrant, and locks can suffer from priority inversion. To support coordination between system callbacks, a high-priority thread created with PortTime, and the main application thread, PortMidi uses a lock-free, non-blocking queue. The queue implementation is not particular to MIDI and is available for other uses.