QSDK 1.1 Documentation

Com::Ptr< T > Struct Template Reference
[QCom]

#include <Q/com.h>

List of all members.

Public Member Functions
	Ptr ()
	Ptr (T *p, bool doAddRef=true)
	Ptr (const Ptr< T > &p)
	~Ptr ()
bool	valid () const
	operator T * () const
T *	operator-> () const
T &	operator * () const
T **	operator & ()
T *const *	operator & () const
Ptr< T > &	operator= (const Ptr< T > &p)
Ptr< T > &	operator= (T *p)

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Detailed Description

template<class T>
struct Com::Ptr< T >

This template class can be used to ease the implementation of reference counting. It is used as a 'smart pointer' and automatically calls methods from the Unknown interface when instances of the template are constructed, assigned and destroyed. The Ptr<T> template should be instantiated with a class derived from Unknown. For the reference counting to be reliable, a user should use instances of Ptr<T> for every long-lived reference to an object (such as class members or global variables). There is a cost associated with the reference count maintenance so care should be taken in the use of Ptr<T> in time-critical algorithms.

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Constructor & Destructor Documentation

template<class T> Com::Ptr< T >::Ptr (   )  [inline]

Create a new smart pointer. The pointer is initialised to zero.

template<class T> Com::Ptr< T >::Ptr (  T *  p, bool  doAddRef = true )  [inline]

Create a new smart pointer with the pointer initialised to p. The reference count of p will be increased by one if the value of doAddRef is true (this is the default).

template<class T> Com::Ptr< T >::Ptr (  const Ptr< T > &  p  )  [inline]

Create a new smart pointer with the pointer initialised from p. The reference count of p will be increased by one.

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

Destroy a smart pointer. The reference count of the interface being pointed to (if any) is decreased by one by calling its Unknown::release method.

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Member Function Documentation

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

The compiler calls this method automatically when the appropriate language construct is used. This makes the smart pointer behave as if it was a regular pointer.

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

The compiler calls this method automatically when the appropriate language construct is used. This makes the smart pointer behave as if it was a regular pointer.

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

The compiler calls this method automatically when the appropriate language construct is used. This makes the smart pointer behave as if it was a regular pointer.

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

The compiler calls this method automatically when the appropriate language construct is used. This makes the smart pointer behave as if it was a regular pointer.

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

The compiler calls this method automatically when the appropriate language construct is used. This makes the smart pointer behave as if it was a regular pointer.

template<class T> Ptr<T>& Com::Ptr< T >::operator= (  T *  p  )  [inline]

Assign one pointer to another by copying the underlying pointer, adjusting reference counts as appropriate.

template<class T> Ptr<T>& Com::Ptr< T >::operator= (  const Ptr< T > &  p  )  [inline]

Assign one pointer to another by copying the underlying pointer, adjusting reference counts as appropriate.

template<class T> bool Com::Ptr< T >::valid (   )  const [inline]

Return true if the reference is valid (i.e. if the pointer is non-zero).

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