RWTTryReadLockGuard<Resource>

Threads Module Reference Guide
Rogue Wave web site: Home Page | Main Documentation Page

RWTTryReadLockGuard<Resource>

Module: Threads Package: Synchronization


RWTTryReadLockGuard<Resource>   RWTLockGuardBase<Resource>

Local Index
Header File
Description
Example
Public Typedef
Public Constructor
Public Destructor
Public Member Function
Private Constructor
Private Member Operator
See Also

Local Index

Members

operator=()
ResourceType

RWTTryReadLockGuard()
tryAcquire()

~RWTTryReadLockGuard()

Header File

#include <rw/sync/RWTTryReadLockGuard.h>

Description

RWTTryReadLockGuard<Resource> is a guard class that tries to acquire read access on its resource upon creation and, if successful, release it upon destruction. Guard objects work in conjunction with block statements in such a way as to establish an appropriate state upon creation, maintain that state for the duration of the block, and restore the original state upon destruction. For example, a guard may acquire read access on a mutex upon creation and release it when destructed. The class used as the actual template parameter for Resource must be one that provides tryAcquireRead and release methods (such as some synchronization classes provided in this module).

Example

#include <rw/sync/RWReadersWriterLock.h>
#include <rw/sync/RWTTryReadLockGuard.h>

RWReadersWriterLock rwlock;

bool foo()
{
  // ...
  {  
     // try to acquire read access on a readers-writer lock:
     RWTTryReadLockGuard<RWReadersWriterLock> lock(rwlock);
     
     // See if the lock was acquired:
     if (!lock.isAcquired()) {
       return false;  // Can't get lock, 
                      // give up and return error
     }
     // ... critical section

     // lock will be released in RWTTryReadLockGuard destructor 
     // before leaving scope, especially important 
     // if an exception might be thrown!
  }

  // ...
  return true;
}

Public Typedef

typedef Resource     ResourceType;

Public Constructor

RWTTryReadLockGuard(Resource& resource);

Constructs an instance with the given resource and attempts to acquire read access on that resource. Uses the inherited isAcquired() member function to see if the acquisition was successful.

Public Destructor

~RWTTryReadLockGuard();

Destructor.

Public Member Function

bool
tryAcquire();

Try again to acquire read access on the resource. Uses this function instead of manipulating the resource directly so that the guard will automatically release it.

Private Constructor

RWTTryReadLockGuard(const RWTTryReadLockGuard<Resource>& second);

Copy construction prohibited.

Private Member Operator

RWTTryReadLockGuard<Resource>&
operator=(const RWTTryReadLockGuard<Resource>& second);

Assignment prohibited.