Read-Write Lock

This group contains the Read-Write Lock implementation. More...

Files
file	corerwlockimpl.h
	This header file provides interfaces of the Read-Write Lock which are only used by the implementation.
file	corerwlock.c
	This source file contains the implementation of _CORE_RWLock_Initialize().
file	corerwlockobtainread.c
	This source file contains the implementation of _CORE_RWLock_Seize_for_reading().
file	corerwlockobtainwrite.c
	This source file contains the implementation of _CORE_RWLock_Seize_for_writing().
file	corerwlockrelease.c
	This source file contains the implementation of _CORE_RWLock_Surrender().

Data Structures
struct	CORE_RWLock_Control

Macros
#define	CORE_RWLOCK_TQ_OPERATIONS   &_Thread_queue_Operations_FIFO
#define	CORE_RWLOCK_THREAD_WAITING_FOR_READ   0
#define	CORE_RWLOCK_THREAD_WAITING_FOR_WRITE   1

Enumerations
enum	CORE_RWLock_States { CORE_RWLOCK_UNLOCKED , CORE_RWLOCK_LOCKED_FOR_READING , CORE_RWLOCK_LOCKED_FOR_WRITING }

Functions
void	_CORE_RWLock_Initialize (CORE_RWLock_Control *the_rwlock)
	Initializes a RWlock.
Status_Control	_CORE_RWLock_Seize_for_reading (CORE_RWLock_Control *the_rwlock, bool wait, Thread_queue_Context *queue_context)
	Obtains RWLock for reading.
Status_Control	_CORE_RWLock_Seize_for_writing (CORE_RWLock_Control *the_rwlock, bool wait, Thread_queue_Context *queue_context)
	Obtains RWLock for writing.
Status_Control	_CORE_RWLock_Surrender (CORE_RWLock_Control *the_rwlock)
	Releases the RWLock.

Detailed Description

This group contains the Read-Write Lock implementation.

Macro Definition Documentation

CORE_RWLOCK_THREAD_WAITING_FOR_READ

#define CORE_RWLOCK_THREAD_WAITING_FOR_READ   0

This is used to denote that a thread is blocking waiting for read-only access to the RWLock.

CORE_RWLOCK_THREAD_WAITING_FOR_WRITE

#define CORE_RWLOCK_THREAD_WAITING_FOR_WRITE   1

This is used to denote that a thread is blocking waiting for write-exclusive access to the RWLock.

Enumeration Type Documentation

CORE_RWLock_States

enum CORE_RWLock_States

RWLock State.

Enumerator
CORE_RWLOCK_UNLOCKED	This indicates the the RWLock is not currently locked.
CORE_RWLOCK_LOCKED_FOR_READING	This indicates the the RWLock is currently locked for reading.
CORE_RWLOCK_LOCKED_FOR_WRITING	This indicates the the RWLock is currently locked for reading.

Function Documentation

_CORE_RWLock_Initialize()

void _CORE_RWLock_Initialize

(

CORE_RWLock_Control *

the_rwlock

)

Initializes a RWlock.

This routine initializes the RWLock.

Parameters

[out]

the_rwlock

is the RWLock to initialize.

_CORE_RWLock_Seize_for_reading()

Status_Control _CORE_RWLock_Seize_for_reading	(	CORE_RWLock_Control *	the_rwlock,
		bool	wait,
		Thread_queue_Context *	queue_context
	)

Obtains RWLock for reading.

This routine attempts to obtain the RWLock for read access.

Parameters

[in,out]	the_rwlock	is the RWLock to wait for
	wait	Indicates whether the calling thread is willing to wait.
	queue_context	The thread queue context.

Return values

STATUS_SUCCESSFUL	The RWlock was successfully seized.
STATUS_UNAVAILABLE	The RWlock is currently locked for writing and the calling thread is not willing to wait.
STATUS_TIMEOUT	A timeout occurred.

_CORE_RWLock_Seize_for_writing()

Status_Control _CORE_RWLock_Seize_for_writing	(	CORE_RWLock_Control *	the_rwlock,
		bool	wait,
		Thread_queue_Context *	queue_context
	)

Obtains RWLock for writing.

This routine attempts to obtain the RWLock for write exclusive access.

Parameters

[in,out]	the_rwlock	The RWLock to wait for.
	wait	Indicates whether the calling thread is willing to wait.
	queue_context	The thread queue context.

Return values

STATUS_SUCCESSFUL	The RWLock was successfully obtained for write exclusive access.
STATUS_UNAVAILABLE	The RWlock is currently locked and the calling thread is not willing to wait.
STATUS_TIMEOUT	A timeout occurred.

_CORE_RWLock_Surrender()

Status_Control _CORE_RWLock_Surrender

(

CORE_RWLock_Control *

the_rwlock

)

Releases the RWLock.

This routine manually releases the_rwlock. All of the threads waiting for the RWLock will be readied.

Parameters

[in,out]

the_rwlock

The RWLock to surrender.

Returns

STATUS_SUCCESSFUL This method is always successful.