PIReadWriteLock Class Reference

Synchronization primitive that allows concurrent readers and exclusive writer access. More...

#include <pireadwritelock.h>

Public Member Functions
PIReadWriteLock	PIReadWriteLock ()
	Constructs PIReadWriteLock.
	~PIReadWriteLock ()
	Destroy PIReadWriteLock.
void	lockWrite ()
	Acquires writer access, waiting until there are no active readers or writer.
bool	tryLockWrite ()
	Tries to acquire writer access without waiting.
bool	tryLockWrite (PISystemTime timeout)
	Tries to acquire writer access within timeout.
void	unlockWrite ()
	Releases writer access and wakes waiting threads.
void	lockRead ()
	Acquires one reader slot, waiting while writer access is active.
bool	tryLockRead ()
	Tries to acquire reader access without waiting.
bool	tryLockRead (PISystemTime timeout)
	Tries to acquire reader access within timeout.
void	unlockRead ()
	Releases one reader slot and wakes waiting threads.

Detailed Description

Synchronization primitive that allows concurrent readers and exclusive writer access.

Read/Write lock.

Synopsis

PIReadWriteLock provides more complex critical code section defence between several threads. PIReadWriteLock permit only one thread to modify data, besides multiple thread can read data simultaneously. Conatains methods: lockWrite(), tryLockWrite(), unlockWrite(), lockRead(), tryLockRead() and unlockRead().

For automatic read and write locks use PIReadLocker and PIWriteLocker.

Usage

When one thread lock for write with lockWrite(), all other threads (read and write) can`t access data until this thread call unlockWrite(). In this way, write lock works similar to mutex.

On the other hand, several threads can simultaneously read data. In other words, lockRead() increase read threads counter and unlockRead() decrease. But thread can`t read data while other thread locked for write.