P::RWLock Class Reference
[Core library]

Read-write lock synchronization object. More...

#include <prwlock.h>

List of all members.

Public Member Functions
	RWLock (const char *name=0) throw (SyncError)
	Default constructor.
	~RWLock () throw ()
	Destructor.
void	readLock () throw (SyncError)
	Lock the read-write lock for reading.
bool	tryReadLock (unsigned int timeout) throw (SyncError)
	Try to lock the read-write lock for reading with timeout.
void	writeLock () throw (SyncError)
	Lock the read-write lock for writing.
bool	tryWriteLock (unsigned int timeout) throw (SyncError)
	Try to lock the mutex for writing with timeout.
void	unlock () throw (SyncError)
	Release the previously acquired lock.

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Detailed Description

Read-write lock synchronization object.

A read-write lock is like a mutex but allows multiple readers or one writer to hold the lock at the same time. Also, read-write locks are not recursive. On Win32 systems the read-write lock is implemented using a mutex which does not allow multiple readers.

See also:

Mutex

Author:

Christian Prochnow <cproch@seculogix.de>

Definition at line 38 of file prwlock.h.

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Constructor & Destructor Documentation

P::RWLock::RWLock (  const char *  name = 0  )  throw (SyncError)

Default constructor. Construct the RWLock object. If a name is given, the read-write lock can be shared by multiple processes, otherwise a process- local rwlock is created. On POSIX systems that support SYSV shared memory process-shared rwlock's are implemented using a shared memory segment which contains the pthread_rwlock_t structure. Parameters: name  a pointer to the name of the rwlock which is used to identify it, or a NULL pointer if the mutex should be process-local. On POSIX systems the name must reffer to an existing file and the process must be able to stat() the file. Exceptions: SyncError

P::RWLock::~RWLock (   )  throw ()

Destructor. The destructor destroys the read-write lock. The rwlock must be in unlocked state when the destructor is called. On POSIX systems this also removes the shared memory segment which contains the pthread_rwlock_t structure if no more processes reference to it.

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Member Function Documentation

void P::RWLock::readLock (   )  throw (SyncError)

Lock the read-write lock for reading. If the read-write lock is currently locked for writing by another thread the calling thread suspends until the write-lock has been released. If another thread already holds a read-lock, or the read- write lock is currently unlocked the function returns immediatly. Exceptions: SyncError  Referenced by P::RWLock::ReadLock::operator=().

bool P::RWLock::tryReadLock (  unsigned int  timeout  )  throw (SyncError)

Try to lock the read-write lock for reading with timeout. This method does the same than readLock() but also supports a timeout- value. If the read-lock cannot be acquired in the given interval the method returns without locking the rwlock and a FALSE return value. Parameters: timeout  the timeout in milliseconds to wait for the read-lock. If zero is specified the method returns immediatly. Returns: TRUE if the read-lock has been acquired, FALSE otherwise. Exceptions: SyncError

bool P::RWLock::tryWriteLock (  unsigned int  timeout  )  throw (SyncError)

Try to lock the mutex for writing with timeout. This method does the same than writeLock() but also supports a timeout- value. If the lock cannot be acquired in the given interval the method returns without locking the rwlock and a FALSE return value. Parameters: timeout  the timeout in milliseconds to wait for the read-lock. If zero is specified the method returns immediatly. Returns: TRUE if the write-lock has been acquired, FALSE otherwise. Exceptions: SyncError

void P::RWLock::unlock (   )  throw (SyncError)

Release the previously acquired lock.

void P::RWLock::writeLock (   )  throw (SyncError)

Lock the read-write lock for writing. If the read-write lock is currently locked for reading or writing by another thread, the calling thread suspends until the lock has been released. If the read-write lock is currently unlocked, the function returns immediatly. Exceptions: SyncError  Referenced by P::RWLock::WriteLock::operator=().

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

• prwlock.h

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