RWNullMutexLock Class Reference

Efficient stand-in for a mutual exclusion lock when synchronization 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 RWTReadUnlockGuard< RWNullMutexLock >	ReadUnlockGuard
typedef RWTTryLockGuard< RWNullMutexLock >	TryLockGuard
typedef RWTTryReadLockGuard< RWNullMutexLock >	TryReadLockGuard
typedef RWTTryWriteLockGuard< RWNullMutexLock >	TryWriteLockGuard
typedef RWTUnlockGuard< RWNullMutexLock >	UnlockGuard
typedef RWTWriteLockGuard< RWNullMutexLock >	WriteLockGuard
typedef RWTWriteUnlockGuard< RWNullMutexLock >	WriteUnlockGuard

Public Member Functions
	RWNullMutexLock (RWCancellationState state=0)
	RWNullMutexLock (RWStaticCtor)
	~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 ()
Public Member Functions inherited from RWSynchObject
void	disableCancellation ()
void	enableCancellation (RWCancellationState)
bool	isCancellationEnabled () const
void	setCancellation (RWCancellationState)

Private Member Functions
	RWNullMutexLock (const RWNullMutexLock &second)
RWNullMutexLock &	operator= (const RWNullMutexLock &second)

Additional Inherited Members
Protected Member Functions inherited from RWSynchObject
	RWSynchObject (const RWSynchObject &second)
	RWSynchObject (RWCancellationState state=0)
	RWSynchObject (RWStaticCtor)
RWSynchObject &	operator= (const RWSynchObject &second)
void	testCancellation ()
Related Symbols inherited from RWSynchObject
#define	RW_CANCELLATION_DISABLED
#define	RW_CANCELLATION_ENABLED
typedef void(*	RWCancellationState) ()
void	rwServiceCancellation (void)

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.

Example

#include <rw/sync/RWMutexLock.h>
#include <rw/sync/RWNullMutexLock.h>
 
int main() {
  RWNullMutexLock mutex;
 
  mutex.acquire();  // No cost if synchronization not required
  // critical section
  mutex.release();
 
  // Same thing, this time using a guard:
  {
    RWNullMutexLock::Lockguard lock(mutex);  // does nothing if
                                             // synchronization not
                                             // required critical section
 
    // If synchronization required, lock will be released
    // automatically
  }
}

See also

RWMutexLock, RWTLockGuard, RWTUnlockGuard, RWTTryLockGuard

Member Typedef Documentation

LockGuard

typedef RWTLockGuard<RWNullMutexLock> RWNullMutexLock::LockGuard

Predefined type for compatible guard.

ReadLockGuard

typedef RWTReadLockGuard<RWNullMutexLock> RWNullMutexLock::ReadLockGuard

Predefined type for compatible guard.

ReadUnlockGuard

typedef RWTReadUnlockGuard<RWNullMutexLock> RWNullMutexLock::ReadUnlockGuard

Predefined type for compatible guard.

TryLockGuard

typedef RWTTryLockGuard<RWNullMutexLock> RWNullMutexLock::TryLockGuard

Predefined type for compatible guard.

TryReadLockGuard

typedef RWTTryReadLockGuard<RWNullMutexLock> RWNullMutexLock::TryReadLockGuard

Predefined type for compatible guard.

TryWriteLockGuard

typedef RWTTryWriteLockGuard<RWNullMutexLock> RWNullMutexLock::TryWriteLockGuard

Predefined type for compatible guard.

UnlockGuard

typedef RWTUnlockGuard<RWNullMutexLock> RWNullMutexLock::UnlockGuard

Predefined type for compatible guard.

WriteLockGuard

typedef RWTWriteLockGuard<RWNullMutexLock> RWNullMutexLock::WriteLockGuard

Predefined type for compatible guard.

WriteUnlockGuard

typedef RWTWriteUnlockGuard<RWNullMutexLock> RWNullMutexLock::WriteUnlockGuard

Predefined type for compatible guard.

Constructor & Destructor Documentation

RWNullMutexLock() [1/3]

RWNullMutexLock::RWNullMutexLock ( RWStaticCtor )

inline

Constructs a static instance, but does no direct initialization. The RWNullMutexLock is initialized on first use.

This constructor must be used only for static instances. Use of this constructor with an automatically or dynamically allocated instance produces errors or other unpredictable behavior.

Static instances are zero initialized, which results in an RWNullMutexLock with a cancellation state of RW_CANCELLATION_DISABLED.

RWNullMutexLock() [2/3]

RWNullMutexLock::RWNullMutexLock ( RWCancellationState state = 0 )

inline

Creates an RWNullMutexLock. The parameter state is currently ignored.

~RWNullMutexLock()

RWNullMutexLock::~RWNullMutexLock ( )

inline

Destructor.

RWNullMutexLock() [3/3]

RWNullMutexLock::RWNullMutexLock ( const RWNullMutexLock & second )

private

Copy construction prohibited.

Member Function Documentation

acquire() [1/2]

void RWNullMutexLock::acquire ( )

inline

Does nothing.

acquire() [2/2]

RWWaitStatus RWNullMutexLock::acquire ( unsigned long milliseconds )

inline

Returns RW_THR_ACQUIRED.

acquireRead() [1/2]

void RWNullMutexLock::acquireRead ( )

inline

Does nothing.

acquireRead() [2/2]

RWWaitStatus RWNullMutexLock::acquireRead ( unsigned long milliseconds )

inline

Returns RW_THR_ACQUIRED.

acquireWrite() [1/2]

void RWNullMutexLock::acquireWrite ( )

inline

Does nothing.

acquireWrite() [2/2]

RWWaitStatus RWNullMutexLock::acquireWrite ( unsigned long milliseconds )

inline

Returns RW_THR_ACQUIRED.

isAcquired()

bool RWNullMutexLock::isAcquired

(

)

const

Returns true.

Condition:

Available only from the debug version of the Threads Module.

operator=()

RWNullMutexLock & RWNullMutexLock::operator= ( const RWNullMutexLock & second )

private

Assignment prohibited.

release()

void RWNullMutexLock::release ( )

inline

Does nothing.

tryAcquire()

bool RWNullMutexLock::tryAcquire ( )

inline

Returns true.

tryAcquireRead()

bool RWNullMutexLock::tryAcquireRead ( )

inline

Returns true.

tryAcquireWrite()

bool RWNullMutexLock::tryAcquireWrite ( )

inline

Returns true.