TMCCountedPtr< T > Class Template Reference
[MCCore]

List of all members.

Public Member Functions
	TMCCountedPtr ()
	TMCCountedPtr (T *lp)
	TMCCountedPtr (const TMCCountedPtr< T > &lp)
	~TMCCountedPtr ()
uint32	Release ()
	operator T * () const
T &	operator * () const
T **	operator & ()
T *const *	operator & () const
TMCCountedPtr< T > *	GetAddress ()
T *	operator-> () const
T *	operator= (T *lp)
T *	operator= (const TMCCountedPtr< T > &lp)
boolean	operator== (const TMCCountedPtr< T > &rhs) const
boolean	operator== (const T *rhs) const
BOOL	operator! ()
void	CheckLastRef (void)
Static Public Member Functions
T *	Assign (T **pp, T *lp)
Public Attributes
T *	fObject

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Detailed Description

template<class T>
class TMCCountedPtr< T >

Counted objects are objects that use a counter to keep track of how many other objects need them, and delete themselves when nobody needs them anymore. A counted object has an AddRef method that increments its counter, and a Release method that decrements it. When the value of the counter reaches zero, the object is deleted.

It is possible to call AddRef and Release "by hand" but it is a bad idea for at least two reasons. First, it is very easy to forget to add a call to Release, therefore causing a memory leak. Second the code becomes more complex because in every function that calls AddRef, you must consider exceptions. So you have to use a try/catch block, add a call to Release at the end of the try AND another one before re-throwing in the catch section...

Because they automatically call AddRef and Release, TMCCountedPtr, TMCCountedGetHelper and TMCCountedCreateHelper are your best friends.

TMCCountedPtr overrides many operators (including *, ->, &, =, and cast) so that you can use it like other pointers (the difference being the calls to AddRef and Release when you assign the pointer). Here is a pseudo code sample:

        void CountedPointersSample()
    {
                TMCCountedPtr<IMCFile> file;                            //a counted pointer to a file object (initialized to NULL)
                gFileUtilities->CreateIMCFile(&file);           //ask the application to create a file (its refcount will be 1)
                IMCFile* file2= pfile;                                          //that's legal (but doesn't addref)
                if (MCVerify(file))                                                     //just to illustrate a test with an assert
                {
                        TMCCountedPtr<IMCFile> file3;
                        file3= file2;                                                   //the refcount becomes 2 because file3 is a counted pointer
                }                                                                                       //the refcount becomes 1 as the destructor of file3 is called
                file = NULL;                                                            //the refcount becomes 0 and the file object is deleted.
                //at this point file2 is invalid. Lets set it to null so nobody corrupts the memory by trying to use it.
                file2= NULL;
        }

Note:

When using counted pointers as class members, you must be careful and avoid creating cycles (two or more objects pointing to each other). If you have cycles, the objects will never be deleted...

For more information, please refer to the "Counted Pointers" chapter in the overview of the SDK.

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Constructor & Destructor Documentation

template<class T> TMCCountedPtr< T >::TMCCountedPtr (   )  [inline]

template<class T> TMCCountedPtr< T >::TMCCountedPtr (  T *  lp  )  [inline]

template<class T> TMCCountedPtr< T >::TMCCountedPtr (  const TMCCountedPtr< T > &  lp  )  [inline]

template<class T> TMCCountedPtr< T >::~TMCCountedPtr (   )  [inline]

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Member Function Documentation

template<class T> T* TMCCountedPtr< T >::Assign (  T **  pp, T *  lp )  [inline, static]

template<class T> void TMCCountedPtr< T >::CheckLastRef (  void   )  [inline]

template<class T> TMCCountedPtr<T>* TMCCountedPtr< T >::GetAddress (   )  [inline]

template<class T> T* const* TMCCountedPtr< T >::operator & (   )  const [inline]

template<class T> T** TMCCountedPtr< T >::operator & (   )  [inline]

template<class T> T& TMCCountedPtr< T >::operator * (   )  const [inline]

template<class T> TMCCountedPtr< T >::operator T * (   )  const [inline]

template<class T> BOOL TMCCountedPtr< T >::operator! (   )  [inline]

template<class T> T* TMCCountedPtr< T >::operator-> (   )  const [inline]

template<class T> T* TMCCountedPtr< T >::operator= (  const TMCCountedPtr< T > &  lp  )  [inline]

template<class T> T* TMCCountedPtr< T >::operator= (  T *  lp  )  [inline]

template<class T> boolean TMCCountedPtr< T >::operator== (  const T *  rhs  )  const [inline]

template<class T> boolean TMCCountedPtr< T >::operator== (  const TMCCountedPtr< T > &  rhs  )  const [inline]

template<class T> uint32 TMCCountedPtr< T >::Release (   )  [inline]

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Member Data Documentation

template<class T> T* TMCCountedPtr< T >::fObject

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The documentation for this class was generated from the following file:

• MCCountedPtr.h

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