Class template intrusive

Class template intrusive_ptr

boost::interprocess::intrusive_ptr

Synopsis

// In header: <boost/interprocess/smart_ptr/intrusive_ptr.hpp>

template<typename T, typename VoidPointer> 
class intrusive_ptr {
public:
  // types
  typedef boost::intrusive::pointer_traits< VoidPointer >::template rebind_pointer< T >::type pointer;       // Provides the type of the internal stored pointer. 
  typedef T                                                                                   element_type;  // Provides the type of the stored pointer. 

  // construct/copy/destruct
  intrusive_ptr();
  intrusive_ptr(const pointer &, bool = true);
  intrusive_ptr(intrusive_ptr const &);
  template<typename U> intrusive_ptr(intrusive_ptr< U, VP > const &);
  intrusive_ptr& operator=(intrusive_ptr const &);
  template<typename U> 
    intrusive_ptr& operator=(intrusive_ptr< U, VP > const &);
  intrusive_ptr& operator=(pointer);
  ~intrusive_ptr();

  // public member functions
  pointer & get();
  const pointer & get() const;
  T & operator*() const;
  const pointer & operator->() const;
  pointer & operator->();
  operator unspecified_bool_type() const;
  bool operator!() const;
  void swap(intrusive_ptr &);
};

Description

The intrusive_ptr class template stores a pointer to an object with an embedded reference count. intrusive_ptr is parameterized on T (the type of the object pointed to) and VoidPointer(a void pointer type that defines the type of pointer that intrusive_ptr will store). intrusive_ptr<T, void *> defines a class with a T* member whereas intrusive_ptr<T, offset_ptr<void> > defines a class with a offset_ptr<T> member. Relies on unqualified calls to:

void intrusive_ptr_add_ref(T * p); void intrusive_ptr_release(T * p);

with (p != 0)

The object is responsible for destroying itself.

`intrusive_ptr` public construct/copy/destruct

```
intrusive_ptr();
```
Constructor. Initializes internal pointer to 0. Does not throw
```
intrusive_ptr(const pointer & p, bool add_ref = true);
```
Constructor. Copies pointer and if "p" is not zero and "add_ref" is true calls intrusive_ptr_add_ref(to_raw_pointer(p)). Does not throw
```
intrusive_ptr(intrusive_ptr const & rhs);
```
Copy constructor. Copies the internal pointer and if "p" is not zero calls intrusive_ptr_add_ref(to_raw_pointer(p)). Does not throw
```
template<typename U> intrusive_ptr(intrusive_ptr< U, VP > const & rhs);
```
Constructor from related. Copies the internal pointer and if "p" is not zero calls intrusive_ptr_add_ref(to_raw_pointer(p)). Does not throw
```
intrusive_ptr& operator=(intrusive_ptr const & rhs);
```
Assignment operator. Equivalent to intrusive_ptr(r).swap(*this). Does not throw

template<typename U> 
  intrusive_ptr& operator=(intrusive_ptr< U, VP > const & rhs);

Assignment from related. Equivalent to intrusive_ptr(r).swap(*this). Does not throw

```
intrusive_ptr& operator=(pointer rhs);
```
Assignment from pointer. Equivalent to intrusive_ptr(r).swap(*this). Does not throw
```
~intrusive_ptr();
```
Destructor. If internal pointer is not 0, calls intrusive_ptr_release(to_raw_pointer(m_ptr)). Does not throw

`intrusive_ptr` public member functions

```
pointer & get();
```
Returns a reference to the internal pointer. Does not throw
```
const pointer & get() const;
```
Returns a reference to the internal pointer. Does not throw
```
T & operator*() const;
```
Returns *get(). Does not throw
```
const pointer & operator->() const;
```
Returns *get(). Does not throw
```
pointer & operator->();
```
Returns get(). Does not throw
```
operator unspecified_bool_type() const;
```
Conversion to boolean. Does not throw
```
bool operator!() const;
```
Not operator. Does not throw
```
void swap(intrusive_ptr & rhs);
```
Exchanges the contents of the two smart pointers. Does not throw