ReadWriteLock Class Reference

objects of this class organize a read-write-lock mechanism. This class is mainly used by dataObject. If this object is locked for writing (lockWrite), it can not be used for reading nor writing until the writer released the protection with (unlock). On the other hand, the object can multiply be locked for reading if no write-operation is executed at the same time. More...

#include <readWriteLock.h>

List of all members.

Public Member Functions
	ReadWriteLock (int lockStatus=0)
	constructor
	~ReadWriteLock ()
	deconstructor
void	lockRead (int increment=1)
	locks for reading
void	lockWrite ()
	locks for writing
void	unlock ()
	unlocks a read or write protection
void	_unlock (int value)
	unlocks a read or write protection depending on the given integer value
int	getLockStatus () const
	returns the protection state
Private Member Functions
	ReadWriteLock (const ReadWriteLock &)
Private Attributes
int	nrOfReaders
int	status
	nrOfReaders (>= 0)
bool	writeGelocked
	state (-1 if object is in write mode, 0 if object is idle, else number of readers)
pthread_mutex_t	mAtomicOp
pthread_mutex_t	mReadLock
	critical section for realizing atomic operation blocks
pthread_mutex_t	mWriteLock
	critical section for realizing the read lock

---

Detailed Description

objects of this class organize a read-write-lock mechanism. This class is mainly used by dataObject. If this object is locked for writing (lockWrite), it can not be used for reading nor writing until the writer released the protection with (unlock). On the other hand, the object can multiply be locked for reading if no write-operation is executed at the same time.

---

Constructor & Destructor Documentation

ReadWriteLock::ReadWriteLock

(

int

lockStatus = 0

)

[inline]

constructor

Parameters:

int	lockStatus = 0, should normally be used with the default parameter, else: lockStatus: -1 writeLock, 0 no lock, >0 read lock with given number of readers

---

Member Function Documentation

void ReadWriteLock::_unlock

(

int

value

)

[inline]

unlocks a read or write protection depending on the given integer value

Parameters:

int	value (-1 : unlocks write protection, >0 unlocks the given number of reading protections)

int ReadWriteLock::getLockStatus

(

)

const [inline]

returns the protection state

Returns:

-1 if object is in write mode, 0 if object is idle, else number of readers

void ReadWriteLock::lockRead

(

int

increment = 1

)

[inline]

locks for reading

locks this object for reading. This method waits until the object is not protected by any write operation and then locks it for reading. If other participants are already reading this object, the number of readers variable is just incremented

Parameters:

int	increment, number of new readers

void ReadWriteLock::lockWrite

(

)

[inline]

locks for writing

locks this object for writing. This method waits until this object is in idle mode and then locks it for one single writing operation.

void ReadWriteLock::unlock

(

)

[inline]

unlocks a read or write protection

If this object is in write-mode, this write-protection is unlocked. Else the number of readers is decremented. The reading-protection is finally unlocked, if no other reader is reading the object.

---

The documentation for this class was generated from the following file:

• D:/itom-git/sources/itom/DataObject/readWriteLock.h