RWNullMutexLock Class Reference
[Synchronization]

Efficient stand-in for a mutual exclusion lock when synchroniztion is either unnecessary or not important. More...

#include <rw/sync/RWNullMutexLock.h>

Inheritance diagram for RWNullMutexLock:

Public Types
typedef RWTLockGuard < RWNullMutexLock >	LockGuard
typedef RWTReadLockGuard < RWNullMutexLock >	ReadLockGuard
typedef RWTWriteLockGuard < RWNullMutexLock >	WriteLockGuard
typedef RWTTryLockGuard < RWNullMutexLock >	TryLockGuard
typedef RWTTryReadLockGuard < RWNullMutexLock >	TryReadLockGuard
typedef RWTTryWriteLockGuard < RWNullMutexLock >	TryWriteLockGuard
typedef RWTUnlockGuard < RWNullMutexLock >	UnlockGuard
typedef RWTReadUnlockGuard < RWNullMutexLock >	ReadUnlockGuard
typedef RWTWriteUnlockGuard < RWNullMutexLock >	WriteUnlockGuard
Public Member Functions
	RWNullMutexLock (RWStaticCtor)
	RWNullMutexLock (RWCancellationState state=0)
	~RWNullMutexLock ()
void	acquire ()
RWWaitStatus	acquire (unsigned long milliseconds)
void	acquireRead ()
RWWaitStatus	acquireRead (unsigned long milliseconds)
void	acquireWrite ()
RWWaitStatus	acquireWrite (unsigned long milliseconds)
bool	isAcquired () const
void	release ()
bool	tryAcquire ()
bool	tryAcquireRead ()
bool	tryAcquireWrite ()
Private Member Functions
	RWNullMutexLock (const RWNullMutexLock &second)
RWNullMutexLock &	operator= (const RWNullMutexLock &second)

Detailed Description

An RWNullMutexLock is an efficient stand-in for a mutual exclusion lock, particularly when you know that critical sections of code do not need synchronization. For example, you may know that it is not possible for more than one thread to simultaneously enter a section of code that would otherwise require locking. In such cases, you can use an RWNullMutexLock to eliminate the unnecessary overhead of acquiring and releasing a mutex. This class can also be used to instantiate a single-threaded or non-thread-safe version of the template classes that accept a mutex parameter, such as RWTMonitor<Mutex> .

Examples

 #include <rw/sync/RWMutexLock.h>
 #include <rw/sync/RWNullMutexLock.h>

 #if SYNCHRONIZATION_REQUIRED
 typedef RWMutexLock MUTEX;
 #else
 typedef RWNullMutexLock MUTEX;
 #endif

 MUTEX mutex;

 mutex.acquire();  // No cost if synchronization not required
 // critical section
 mutex.release();

 // Same thing, this time using a guard:
 {
    MUTEX::Lockguard lock(mutex); // does nothing if
                                  // synchronization not required
    // critical section

    // If synchronization required, lock will be released
    // automatically
 }

See also:: RWMutexLock, RWTLockGuard<Resource>, RWTUnlockGuard<Resource>, RWTTryLockGuard<Resource>