DtRdWrLock__rti__ Class Reference

Platform independent read-lock / write-lock. More...

Inheritance diagram for DtRdWrLock__rti__:

Collaboration diagram for DtRdWrLock__rti__:

Public Member Functions
	DtRdWrLock__rti__ ()
	default constructor
virtual	~DtRdWrLock__rti__ ()
	destructor
virtual void	init ()
	initialize the locking mechanism
virtual void	destroy ()
	destroy the lock
virtual int	wrLock ()
	lock the protected resource for writing. Return 0 if lock acquired.
virtual int	rdLock ()
	lock the protected resource for reading. Return 0 if lock acquired.
virtual int	wrUnlock ()
	unlock the write-lock on the protected resource.
virtual int	rdUnlock ()
	unlock the read-lock on the protected resource.

Protected Member Functions
	DtRdWrLock__rti__ (const DtRdWrLock__rti__ &orig)
	copy constructor
const DtRdWrLock__rti__ &	operator= (const DtRdWrLock__rti__ &orig)
	assignment operator

Protected Attributes
volatile long	readers
	The Win32 implementation uses two counters and the Interlocked Variable Access facility to create a lightweight locking mechanism.
volatile long	writers
pthread_rwlock_t	myPtLock
pthread_rwlock_t *	myLock

Detailed Description

Platform independent read-lock / write-lock.

Instances of DtRdWrLock are used to provide a platform independent read-lock / write-lock mechanism for use by threads of the same process. Do not use this class to implement inter-process comm- unication between threads of different processes.

Constructor & Destructor Documentation

DtRdWrLock__rti__::DtRdWrLock__rti__

(

)

default constructor

DtRdWrLock__rti__::DtRdWrLock__rti__ ( const DtRdWrLock__rti__ &  orig )

protected

copy constructor

DtRdWrLock__rti__::~DtRdWrLock__rti__ ( )

virtual

destructor

References readers, and writers.

Member Function Documentation

void DtRdWrLock__rti__::destroy ( )

virtual

destroy the lock

Reimplemented in DtIpcRdWrLock__rti__.

References myLock, readers, and writers.

void DtRdWrLock__rti__::init ( )

virtual

initialize the locking mechanism

Reimplemented in DtIpcRdWrLock__rti__.

References myLock, myPtLock, NULL, readers, and writers.

const DtRdWrLock__rti__ & DtRdWrLock__rti__::operator= ( const DtRdWrLock__rti__ &  orig )

protected

assignment operator

int DtRdWrLock__rti__::rdLock ( )

virtual

lock the protected resource for reading. Return 0 if lock acquired.

References myLock, readers, and writers.

Referenced by DtSmSubscribableMessageQueue__rti__::lockForRead().

int DtRdWrLock__rti__::rdUnlock ( )

virtual

unlock the read-lock on the protected resource.

Return 0 if lock released.

References myLock, and readers.

Referenced by DtSmSubscribableMessageQueue__rti__::unlockForRead().

int DtRdWrLock__rti__::wrLock ( )

virtual

lock the protected resource for writing. Return 0 if lock acquired.

References myLock, readers, and writers.

Referenced by DtSmSubscribableMessageQueue__rti__::lockForWrite().

int DtRdWrLock__rti__::wrUnlock ( )

virtual

unlock the write-lock on the protected resource.

Return 0 if lock released.

References myLock, and writers.

Referenced by DtSmSubscribableMessageQueue__rti__::unlockForWrite().

Member Data Documentation

pthread_rwlock_t* DtRdWrLock__rti__::myLock

protected

Referenced by DtIpcRdWrLock__rti__::destroy(), destroy(), DtIpcRdWrLock__rti__::DtIpcRdWrLock__rti__(), DtIpcRdWrLock__rti__::init(), init(), rdLock(), rdUnlock(), wrLock(), and wrUnlock().

pthread_rwlock_t DtRdWrLock__rti__::myPtLock

protected

Referenced by init().

volatile long DtRdWrLock__rti__::readers

protected

The Win32 implementation uses two counters and the Interlocked Variable Access facility to create a lightweight locking mechanism.

("Lightweight" because it doesn't use semaphores, which are slower). However since the counters are limited in scope to the process that creates them (and any threads that inherit from that process) this mechanism cannot be used for inter-process locking, only intra-process thread locking. In order to avoid having two different ctors for Windows and *nix implementations these counters are present in both implementations and initialized in the ctor init-list, however they are unused in *nix builds This implementation is first-come, first-served which favors writers over readers.

Referenced by DtIpcRdWrLock__rti__::destroy(), destroy(), init(), rdLock(), rdUnlock(), wrLock(), DtIpcRdWrLock__rti__::~DtIpcRdWrLock__rti__(), and ~DtRdWrLock__rti__().

volatile long DtRdWrLock__rti__::writers

protected

Referenced by destroy(), init(), rdLock(), wrLock(), wrUnlock(), and ~DtRdWrLock__rti__().

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

• vlRdWrLock__rti__.h
• vlRdWrLock__rti__.cxx