Collaboration diagram for I/O Queues:

Detailed Description

ChibiOS/RT queues are mostly used in serial-like device drivers. The device drivers are usually designed to have a lower side (lower driver, it is usually an interrupt service routine) and an upper side (upper driver, accessed by the application threads).
There are several kind of queues:

Input queue, unidirectional queue where the writer is the lower side and the reader is the upper side.
Output queue, unidirectional queue where the writer is the upper side and the reader is the lower side.
Full duplex queue, bidirectional queue. Full duplex queues are implemented by pairing an input queue and an output queue together.

Precondition:: In order to use the I/O queues the CH_USE_QUEUES option must be enabled in chconf.h.

Data Structures
struct	GenericQueue
	Generic I/O queue structure. More...
Functions
void	chIQInit (InputQueue iqp, uint8_t bp, size_t size, qnotify_t infy, void *link)
	Initializes an input queue.
void	chIQResetI (InputQueue *iqp)
	Resets an input queue.
msg_t	chIQPutI (InputQueue *iqp, uint8_t b)
	Input queue write.
msg_t	chIQGetTimeout (InputQueue *iqp, systime_t time)
	Input queue read with timeout.
size_t	chIQReadTimeout (InputQueue iqp, uint8_t bp, size_t n, systime_t time)
	Input queue read with timeout.
void	chOQInit (OutputQueue oqp, uint8_t bp, size_t size, qnotify_t onfy, void *link)
	Initializes an output queue.
void	chOQResetI (OutputQueue *oqp)
	Resets an output queue.
msg_t	chOQPutTimeout (OutputQueue *oqp, uint8_t b, systime_t time)
	Output queue write with timeout.
msg_t	chOQGetI (OutputQueue *oqp)
	Output queue read.
size_t	chOQWriteTimeout (OutputQueue oqp, const uint8_t bp, size_t n, systime_t time)
	Output queue write with timeout.
Queue functions returned status value
#define	Q_OK RDY_OK
	Operation successful.
#define	Q_TIMEOUT RDY_TIMEOUT
	Timeout condition.
#define	Q_RESET RDY_RESET
	Queue has been reset.
#define	Q_EMPTY -3
	Queue empty.
#define	Q_FULL -4
	Queue full,.
Macro Functions
#define	chQSizeI(qp) ((size_t)((qp)->q_top - (qp)->q_buffer))
	Returns the queue's buffer size.
#define	chQSpaceI(qp) ((qp)->q_counter)
	Queue space.
#define	chQGetLink(qp) ((qp)->q_link)
	Returns the queue application-defined link.
#define	chIQGetFullI(iqp) chQSpaceI(iqp)
	Returns the filled space into an input queue.
#define	chIQGetEmptyI(iqp) (chQSizeI(iqp) - chQSpaceI(iqp))
	Returns the empty space into an input queue.
#define	chIQIsEmptyI(iqp) ((bool_t)(chQSpaceI(iqp) <= 0))
	Evaluates to `TRUE` if the specified input queue is empty.
#define	chIQIsFullI(iqp)
	Evaluates to `TRUE` if the specified input queue is full.
#define	chIQGet(iqp) chIQGetTimeout(iqp, TIME_INFINITE)
	Input queue read.
#define	chOQGetFullI(oqp) (chQSizeI(oqp) - chQSpaceI(oqp))
	Returns the filled space into an output queue.
#define	chOQGetEmptyI(oqp) chQSpaceI(oqp)
	Returns the empty space into an output queue.
#define	chOQIsEmptyI(oqp)
	Evaluates to `TRUE` if the specified output queue is empty.
#define	chOQIsFullI(oqp) ((bool_t)(chQSpaceI(oqp) <= 0))
	Evaluates to `TRUE` if the specified output queue is full.
#define	chOQPut(oqp, b) chOQPutTimeout(oqp, b, TIME_INFINITE)
	Output queue write.
Defines
#define	_INPUTQUEUE_DATA(name, buffer, size, inotify, link)
	Data part of a static input queue initializer.
#define	INPUTQUEUE_DECL(name, buffer, size, inotify, link) InputQueue name = _INPUTQUEUE_DATA(name, buffer, size, inotify, link)
	Static input queue initializer.
#define	_OUTPUTQUEUE_DATA(name, buffer, size, onotify, link)
	Data part of a static output queue initializer.
#define	OUTPUTQUEUE_DECL(name, buffer, size, onotify, link) OutputQueue name = _OUTPUTQUEUE_DATA(name, buffer, size, onotify, link)
	Static output queue initializer.
Typedefs
typedef struct GenericQueue	GenericQueue
	Type of a generic I/O queue structure.
typedef void(*	qnotify_t )(GenericQueue *qp)
	Queue notification callback type.
typedef GenericQueue	InputQueue
	Type of an input queue structure.
typedef GenericQueue	OutputQueue
	Type of an output queue structure.

Function Documentation

void chIQInit	(	InputQueue *	iqp,
		uint8_t *	bp,
		size_t	size,
		qnotify_t	infy,
		void *	link
	)

Initializes an input queue.

A Semaphore is internally initialized and works as a counter of the bytes contained in the queue.

Note:: The callback is invoked from within the S-Locked system state, see System States.

Parameters:

[out]	iqp	pointer to an `InputQueue` structure
[in]	bp	pointer to a memory area allocated as queue buffer
[in]	size	size of the queue buffer
[in]	infy	pointer to a callback function that is invoked when data is read from the queue. The value can be `NULL`.
[in]	link	application defined pointer

Function Class:: Initializer, this function just initializes an object and can be invoked before the kernel is initialized.

Definition at line 88 of file chqueues.c.

References GenericQueue::q_buffer, GenericQueue::q_counter, GenericQueue::q_link, GenericQueue::q_notify, GenericQueue::q_rdptr, GenericQueue::q_top, GenericQueue::q_waiting, GenericQueue::q_wrptr, and queue_init.

void chIQResetI ( InputQueue * iqp )

Resets an input queue.

All the data in the input queue is erased and lost, any waiting thread is resumed with status Q_RESET.

Note:: A reset operation can be used by a low level driver in order to obtain immediate attention from the high level layers.

Parameters:

[in] iqp pointer to an InputQueue structure

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 110 of file chqueues.c.

References chDbgCheckClassI(), chSchReadyI(), fifo_remove(), notempty, GenericQueue::q_buffer, GenericQueue::q_counter, GenericQueue::q_rdptr, Q_RESET, GenericQueue::q_waiting, GenericQueue::q_wrptr, and Thread::rdymsg.

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msg_t chIQPutI	(	InputQueue *	iqp,
		uint8_t	b
	)

Input queue write.

A byte value is written into the low end of an input queue.

Parameters:

[in]	iqp	pointer to an `InputQueue` structure
[in]	b	the byte value to be written in the queue

Returns:: The operation status.

Return values:

Q_OK	if the operation has been completed with success.
Q_FULL	if the queue is full and the operation cannot be completed.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 133 of file chqueues.c.

References chDbgCheckClassI(), chIQIsFullI, chSchReadyI(), fifo_remove(), notempty, GenericQueue::q_buffer, GenericQueue::q_counter, Q_FULL, Q_OK, GenericQueue::q_top, GenericQueue::q_waiting, GenericQueue::q_wrptr, and Thread::rdymsg.

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msg_t chIQGetTimeout	(	InputQueue *	iqp,
		systime_t	time
	)

Input queue read with timeout.

This function reads a byte value from an input queue. If the queue is empty then the calling thread is suspended until a byte arrives in the queue or a timeout occurs.

Note:: The callback is invoked before reading the character from the buffer or before entering the state THD_STATE_WTQUEUE.

Parameters:

[in]	iqp	pointer to an `InputQueue` structure
[in]	time	the number of ticks before the operation timeouts, the following special values are allowed: TIME_IMMEDIATE immediate timeout. TIME_INFINITE no timeout.

Returns:: A byte value from the queue.

Return values:

Q_TIMEOUT	if the specified time expired.
Q_RESET	if the queue has been reset.

Function Class:: Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 171 of file chqueues.c.

References chIQIsEmptyI, chSysLock, chSysUnlock, GenericQueue::q_buffer, GenericQueue::q_counter, GenericQueue::q_notify, Q_OK, GenericQueue::q_rdptr, and GenericQueue::q_top.

size_t chIQReadTimeout	(	InputQueue *	iqp,
		uint8_t *	bp,
		size_t	n,
		systime_t	time
	)

Input queue read with timeout.

The function reads data from an input queue into a buffer. The operation completes when the specified amount of data has been transferred or after the specified timeout or if the queue has been reset.

Note:: The function is not atomic, if you need atomicity it is suggested to use a semaphore or a mutex for mutual exclusion.; The callback is invoked before reading each character from the buffer or before entering the state THD_STATE_WTQUEUE.

Parameters:

[in]	iqp	pointer to an `InputQueue` structure
[out]	bp	pointer to the data buffer
[in]	n	the maximum amount of data to be transferred, the value 0 is reserved
[in]	time	the number of ticks before the operation timeouts, the following special values are allowed: TIME_IMMEDIATE immediate timeout. TIME_INFINITE no timeout.

Returns:: The number of bytes effectively transferred.

Function Class:: Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 219 of file chqueues.c.

References chDbgCheck, chIQIsEmptyI, chSysLock, chSysUnlock, GenericQueue::q_buffer, GenericQueue::q_counter, GenericQueue::q_notify, Q_OK, GenericQueue::q_rdptr, GenericQueue::q_top, and TRUE.

void chOQInit	(	OutputQueue *	oqp,
		uint8_t *	bp,
		size_t	size,
		qnotify_t	onfy,
		void *	link
	)

Initializes an output queue.

A Semaphore is internally initialized and works as a counter of the free bytes in the queue.

Note:: The callback is invoked from within the S-Locked system state, see System States.

Parameters:

[out]	oqp	pointer to an `OutputQueue` structure
[in]	bp	pointer to a memory area allocated as queue buffer
[in]	size	size of the queue buffer
[in]	onfy	pointer to a callback function that is invoked when data is written to the queue. The value can be `NULL`.
[in]	link	application defined pointer

Function Class:: Initializer, this function just initializes an object and can be invoked before the kernel is initialized.

Definition at line 268 of file chqueues.c.

References GenericQueue::q_buffer, GenericQueue::q_counter, GenericQueue::q_link, GenericQueue::q_notify, GenericQueue::q_rdptr, GenericQueue::q_top, GenericQueue::q_waiting, GenericQueue::q_wrptr, and queue_init.

void chOQResetI ( OutputQueue * oqp )

Resets an output queue.

All the data in the output queue is erased and lost, any waiting thread is resumed with status Q_RESET.

Note:: A reset operation can be used by a low level driver in order to obtain immediate attention from the high level layers.

Parameters:

[in] oqp pointer to an OutputQueue structure

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 290 of file chqueues.c.

References chDbgCheckClassI(), chQSizeI, chSchReadyI(), fifo_remove(), notempty, GenericQueue::q_buffer, GenericQueue::q_counter, GenericQueue::q_rdptr, Q_RESET, GenericQueue::q_waiting, GenericQueue::q_wrptr, and Thread::rdymsg.

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msg_t chOQPutTimeout	(	OutputQueue *	oqp,
		uint8_t	b,
		systime_t	time
	)

Output queue write with timeout.

This function writes a byte value to an output queue. If the queue is full then the calling thread is suspended until there is space in the queue or a timeout occurs.

Note:: The callback is invoked after writing the character into the buffer.

Parameters:

[in]	oqp	pointer to an `OutputQueue` structure
[in]	b	the byte value to be written in the queue
[in]	time	the number of ticks before the operation timeouts, the following special values are allowed: TIME_IMMEDIATE immediate timeout. TIME_INFINITE no timeout.

Returns:: The operation status.

Return values:

Q_OK	if the operation succeeded.
Q_TIMEOUT	if the specified time expired.
Q_RESET	if the queue has been reset.

Function Class:: Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 322 of file chqueues.c.

References chOQIsFullI, chSysLock, chSysUnlock, GenericQueue::q_buffer, GenericQueue::q_counter, GenericQueue::q_notify, Q_OK, GenericQueue::q_top, and GenericQueue::q_wrptr.

msg_t chOQGetI ( OutputQueue * oqp )

Output queue read.

A byte value is read from the low end of an output queue.

Parameters:

[in] oqp pointer to an OutputQueue structure

Returns:: The byte value from the queue.

Return values:

Q_EMPTY if the queue is empty.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 356 of file chqueues.c.

References chDbgCheckClassI(), chOQIsEmptyI, chSchReadyI(), fifo_remove(), notempty, GenericQueue::q_buffer, GenericQueue::q_counter, Q_EMPTY, Q_OK, GenericQueue::q_rdptr, GenericQueue::q_top, GenericQueue::q_waiting, and Thread::rdymsg.

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size_t chOQWriteTimeout	(	OutputQueue *	oqp,
		const uint8_t *	bp,
		size_t	n,
		systime_t	time
	)

Output queue write with timeout.

The function writes data from a buffer to an output queue. The operation completes when the specified amount of data has been transferred or after the specified timeout or if the queue has been reset.

Note:: The function is not atomic, if you need atomicity it is suggested to use a semaphore or a mutex for mutual exclusion.; The callback is invoked after writing each character into the buffer.

Parameters:

[in]	oqp	pointer to an `OutputQueue` structure
[out]	bp	pointer to the data buffer
[in]	n	the maximum amount of data to be transferred, the value 0 is reserved
[in]	time	the number of ticks before the operation timeouts, the following special values are allowed: TIME_IMMEDIATE immediate timeout. TIME_INFINITE no timeout.

Returns:: The number of bytes effectively transferred.

Function Class:: Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 399 of file chqueues.c.

References chDbgCheck, chOQIsFullI, chSysLock, chSysUnlock, GenericQueue::q_buffer, GenericQueue::q_counter, GenericQueue::q_notify, Q_OK, GenericQueue::q_top, GenericQueue::q_wrptr, and TRUE.

Define Documentation

#define Q_OK RDY_OK

Operation successful.

Definition at line 38 of file chqueues.h.

Referenced by chIQGetTimeout(), chIQPutI(), chIQReadTimeout(), chOQGetI(), chOQPutTimeout(), and chOQWriteTimeout().

#define Q_TIMEOUT RDY_TIMEOUT

Timeout condition.

Definition at line 39 of file chqueues.h.

#define Q_RESET RDY_RESET

Queue has been reset.

Definition at line 40 of file chqueues.h.

Referenced by chIQResetI(), and chOQResetI().

#define Q_EMPTY -3

Queue empty.

Definition at line 41 of file chqueues.h.

Referenced by chOQGetI().

#define Q_FULL -4

Queue full,.

Definition at line 42 of file chqueues.h.

Referenced by chIQPutI().

#define chQSizeI ( qp ) ((size_t)((qp)->q_top - (qp)->q_buffer))

Returns the queue's buffer size.

Parameters:

[in] qp pointer to a GenericQueue structure.

Returns:: The buffer size.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 86 of file chqueues.h.

Referenced by chOQResetI().

#define chQSpaceI ( qp ) ((qp)->q_counter)

Queue space.

Returns the used space if used on an input queue or the empty space if used on an output queue.

Parameters:

[in] qp pointer to a GenericQueue structure.

Returns:: The buffer space.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 98 of file chqueues.h.

#define chQGetLink ( qp ) ((qp)->q_link)

Returns the queue application-defined link.

Note:: This function can be called in any context.

Parameters:

[in] qp pointer to a GenericQueue structure.

Returns:: The application-defined link.

Function Class:: Special function, this function has special requirements see the notes.

Definition at line 109 of file chqueues.h.

#define chIQGetFullI ( iqp ) chQSpaceI(iqp)

Returns the filled space into an input queue.

Parameters:

[in] iqp pointer to an InputQueue structure

Returns:: The number of full bytes in the queue.

Return values:

0	if the queue is empty.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 138 of file chqueues.h.

#define chIQGetEmptyI ( iqp ) (chQSizeI(iqp) - chQSpaceI(iqp))

Returns the empty space into an input queue.

Parameters:

[in] iqp pointer to an InputQueue structure

Returns:: The number of empty bytes in the queue.

Return values:

0	if the queue is full.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 149 of file chqueues.h.

#define chIQIsEmptyI ( iqp ) ((bool_t)(chQSpaceI(iqp) <= 0))

Evaluates to TRUE if the specified input queue is empty.

Parameters:

[in] iqp pointer to an InputQueue structure.

Returns:: The queue status.

Return values:

FALSE	The queue is not empty.
TRUE	The queue is empty.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 161 of file chqueues.h.

Referenced by chIQGetTimeout(), and chIQReadTimeout().

#define chIQIsFullI ( iqp )

Value:

((bool_t)(((iqp)->q_wrptr == (iqp)->q_rdptr) &&   \
                                   ((iqp)->q_counter != 0)))

Evaluates to TRUE if the specified input queue is full.

Parameters:

[in] iqp pointer to an InputQueue structure.

Returns:: The queue status.

Return values:

FALSE	The queue is not full.
TRUE	The queue is full.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 173 of file chqueues.h.

Referenced by chIQPutI().

#define chIQGet ( iqp ) chIQGetTimeout(iqp, TIME_INFINITE)

Input queue read.

This function reads a byte value from an input queue. If the queue is empty then the calling thread is suspended until a byte arrives in the queue.

Parameters:

[in] iqp pointer to an InputQueue structure

Returns:: A byte value from the queue.

Return values:

Q_RESET if the queue has been reset.

Function Class:: Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 188 of file chqueues.h.

#define _INPUTQUEUE_DATA	(	name,
		buffer,
		size,
		inotify,
		link
	)

Value:

{               \
  _THREADSQUEUE_DATA(name),                                                 \
  0,                                                                        \
  (uint8_t *)(buffer),                                                      \
  (uint8_t *)(buffer) + (size),                                             \
  (uint8_t *)(buffer),                                                      \
  (uint8_t *)(buffer),                                                      \
  (inotify),                                                                \
  (link)                                                                    \
}

Data part of a static input queue initializer.

This macro should be used when statically initializing an input queue that is part of a bigger structure.

Parameters:

[in]	name	the name of the input queue variable
[in]	buffer	pointer to the queue buffer area
[in]	size	size of the queue buffer area
[in]	inotify	input notification callback pointer
[in]	link	application defined pointer

Definition at line 202 of file chqueues.h.

#define INPUTQUEUE_DECL	(	name,
		buffer,
		size,
		inotify,
		link
	)	InputQueue name = _INPUTQUEUE_DATA(name, buffer, size, inotify, link)

Static input queue initializer.

Statically initialized input queues require no explicit initialization using chIQInit().

Parameters:

[in]	name	the name of the input queue variable
[in]	buffer	pointer to the queue buffer area
[in]	size	size of the queue buffer area
[in]	inotify	input notification callback pointer
[in]	link	application defined pointer

Definition at line 224 of file chqueues.h.

#define chOQGetFullI ( oqp ) (chQSizeI(oqp) - chQSpaceI(oqp))

Returns the filled space into an output queue.

Parameters:

[in] oqp pointer to an OutputQueue structure

Returns:: The number of full bytes in the queue.

Return values:

0	if the queue is empty.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 253 of file chqueues.h.

#define chOQGetEmptyI ( oqp ) chQSpaceI(oqp)

Returns the empty space into an output queue.

Parameters:

[in] oqp pointer to an OutputQueue structure

Returns:: The number of empty bytes in the queue.

Return values:

0	if the queue is full.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 264 of file chqueues.h.

#define chOQIsEmptyI ( oqp )

Value:

((bool_t)(((oqp)->q_wrptr == (oqp)->q_rdptr) &&   \
                                    ((oqp)->q_counter != 0)))

Evaluates to TRUE if the specified output queue is empty.

Parameters:

[in] oqp pointer to an OutputQueue structure.

Returns:: The queue status.

Return values:

FALSE	The queue is not empty.
TRUE	The queue is empty.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 276 of file chqueues.h.

Referenced by chOQGetI().

#define chOQIsFullI ( oqp ) ((bool_t)(chQSpaceI(oqp) <= 0))

Evaluates to TRUE if the specified output queue is full.

Parameters:

[in] oqp pointer to an OutputQueue structure.

Returns:: The queue status.

Return values:

FALSE	The queue is not full.
TRUE	The queue is full.

Function Class:: This is an I-Class API, this function can be invoked from within a system lock zone by both threads and interrupt handlers.

Definition at line 289 of file chqueues.h.

Referenced by chOQPutTimeout(), and chOQWriteTimeout().

#define chOQPut	(	oqp,
		b
	)	chOQPutTimeout(oqp, b, TIME_INFINITE)

Output queue write.

This function writes a byte value to an output queue. If the queue is full then the calling thread is suspended until there is space in the queue.

Parameters:

[in]	oqp	pointer to an `OutputQueue` structure
[in]	b	the byte value to be written in the queue

Returns:: The operation status.

Return values:

Q_OK	if the operation succeeded.
Q_RESET	if the queue has been reset.

Function Class:: Normal API, this function can be invoked by regular system threads but not from within a lock zone.

Definition at line 305 of file chqueues.h.

#define _OUTPUTQUEUE_DATA	(	name,
		buffer,
		size,
		onotify,
		link
	)

Value:

{              \
  _THREADSQUEUE_DATA(name),                                                 \
  (size),                                                                   \
  (uint8_t *)(buffer),                                                      \
  (uint8_t *)(buffer) + (size),                                             \
  (uint8_t *)(buffer),                                                      \
  (uint8_t *)(buffer),                                                      \
  (onotify),                                                                \
  (link)                                                                    \
}

Data part of a static output queue initializer.

This macro should be used when statically initializing an output queue that is part of a bigger structure.

Parameters:

[in]	name	the name of the output queue variable
[in]	buffer	pointer to the queue buffer area
[in]	size	size of the queue buffer area
[in]	onotify	output notification callback pointer
[in]	link	application defined pointer

Definition at line 319 of file chqueues.h.

#define OUTPUTQUEUE_DECL	(	name,
		buffer,
		size,
		onotify,
		link
	)	OutputQueue name = _OUTPUTQUEUE_DATA(name, buffer, size, onotify, link)

Static output queue initializer.

Statically initialized output queues require no explicit initialization using chOQInit().

Parameters:

[in]	name	the name of the output queue variable
[in]	buffer	pointer to the queue buffer area
[in]	size	size of the queue buffer area
[in]	onotify	output notification callback pointer
[in]	link	application defined pointer

Definition at line 341 of file chqueues.h.

Typedef Documentation

typedef struct GenericQueue GenericQueue

Type of a generic I/O queue structure.

Definition at line 48 of file chqueues.h.

typedef void(* qnotify_t)(GenericQueue *qp)

Queue notification callback type.

Definition at line 51 of file chqueues.h.

typedef GenericQueue InputQueue

Type of an input queue structure.

This structure represents a generic asymmetrical input queue. Writing to the queue is non-blocking and can be performed from interrupt handlers or from within a kernel lock zone (see I-Locked and S-Locked states in System States). Reading the queue can be a blocking operation and is supposed to be performed by a system thread.

Definition at line 123 of file chqueues.h.

typedef GenericQueue OutputQueue

Type of an output queue structure.

This structure represents a generic asymmetrical output queue. Reading from the queue is non-blocking and can be performed from interrupt handlers or from within a kernel lock zone (see I-Locked and S-Locked states in System States). Writing the queue can be a blocking operation and is supposed to be performed by a system thread.

Definition at line 238 of file chqueues.h.

Detailed Description

Data Structures

Functions

Queue functions returned status value

Macro Functions

Defines

Typedefs

Function Documentation

Define Documentation

Typedef Documentation