2.5 Smart Pointer Package

2.5.1 Description

The Threads.h++ Smart Pointer package includes a generic singleton template class, a simple pointer wrapper, and two varieties of thread-safe reference-counted pointers. The classes that provide these features are shown in Figure 8. The Smart Pointer package also provides Threads.h++ with the base classes for handle-body implementation, as shown in Figure 9.

See Chapter 7 of the Threads.h++ User's Guide for a complete information on how to use the Smart Pointer package.

2.5.2 Smart Pointer Class Hierarchy

Figure 8 -- Smart Pointer class hierarchy

The classes in the hierarchy include formal template parameters that represent the types of associated objects. These parameters include:

Body - The type of the pointed-to object

Counter - The type of the reference-counter

Mutex - The type of the synchronization mechanism

Figure 9 -- Handle-body base classes.

2.5.3 Index of Smart Pointer Classes

Table 7 contains an alphabetical listing of the public classes and global functions and macros in the Smart Pointer package.

Table 7 -- Index of Smart Pointer classes

Class Name	Description
*RWBodyBase*	Base class for body classes.
*RWHandleBase*	Base class for handle classes.
*RWSafeCounter*	A typedef that implements the multithread-safe reference-counter, which can be used as the counter template parameter for *RWTCountingPointer*.
*RWTCountedPointer<Body>*	A smart pointer class that is intended for use as a handle to a reference-counting body.
*RWTCounter<Mutex>*	The counter type used by the *RWTCountingPointer* class.
*RWTCountingBody<Mutex>*	A base class for classes that must maintain a reference count.
*RWTCountingPointer<Body, Counter=RWSafeCounter>*	Defines a reference-counted pointer that provides reference counting semantics for objects that do not directly support reference counting.
*RWTOnlyPointer<Body>*	An abstraction that simplifies the use of pointers referring to objects on the heap. It doesn't do reference-counting on the body; rather, it is based on the idea of strict ownership semantics.
*RWTPointer<Body>*	Base class for the smart-pointer classes in the pointer package.
*RWTSingleton<T>*	Ensures that a class has only one instance, and provides a global point of access to it.
*RWUnsafeCounter*	A typedef that implements an unsafe counter that can be used for reference counting where multithread safety is not required. This typedef can be used as the counter template parameter for *RWTCountingPointer*.