# Poco

# template < class C >

# class AutoPtr

Library: Foundation
Package: Core
Header: Poco/AutoPtr.h

## Description

AutoPtr is a "smart" pointer for classes implementing reference counting based garbage collection. To be usable with the AutoPtr template, a class must implement the following behaviour: A class must maintain a reference count. The constructors of the object initialize the reference count to one. The class must implement a public duplicate() method:

    void duplicate();

that increments the reference count by one. The class must implement a public release() method:

    void release()

that decrements the reference count by one, and, if the reference count reaches zero, deletes the object.

AutoPtr works in the following way: If an AutoPtr is assigned an ordinary pointer to an object (via the constructor or the assignment operator), it takes ownership of the object and the object's reference count remains unchanged. If the AutoPtr is assigned another AutoPtr, the object's reference count is incremented by one by calling duplicate() on its object. The destructor of AutoPtr calls release() on its object. AutoPtr supports dereferencing with both the -> and the * operator. An attempt to dereference a null AutoPtr results in a NullPointerException being thrown. AutoPtr also implements all relational operators. Note that AutoPtr allows casting of its encapsulated data types.

## Member Summary

Member Functions: assign, cast, duplicate, get, isNull, operator !, operator !=, operator *, operator <, operator <=, operator =, operator ==, operator >, operator >=, operator C *, operator const C *, operator->, reset, swap, unsafeCast

## Constructors

### AutoPtr

AutoPtr();

### AutoPtr

AutoPtr(
C * ptr
);

### AutoPtr

AutoPtr(
const AutoPtr & ptr
);

### AutoPtr

AutoPtr(
AutoPtr && ptr
) noexcept;

### AutoPtr

template < class Other > AutoPtr(
const AutoPtr < Other > & ptr
);

### AutoPtr

AutoPtr(
C * ptr,
bool shared
);

## Destructor

### ~AutoPtr

~AutoPtr();

## Member Functions

### assign

AutoPtr & assign(
C * ptr
);

### assign

AutoPtr & assign(
C * ptr,
bool shared
);

### assign

AutoPtr & assign(
const AutoPtr & ptr
);

### assign

template < class Other > AutoPtr & assign(
const AutoPtr < Other > & ptr
);

### cast

template < class Other > AutoPtr < Other > cast() const;

Casts the AutoPtr via a dynamic cast to the given type. Returns an AutoPtr containing nullptr if the cast fails. Example: (assume class Sub: public Super)

    AutoPtr<Super> super(new Sub());
    AutoPtr<Sub> sub = super.cast<Sub>();
    poco_assert (sub.get());

### duplicate

C * duplicate();

### get

C * get();

### get

const C * get() const;

### isNull

bool isNull() const;

### operator !

bool operator ! () const;

### operator !=

bool operator != (
const AutoPtr & ptr
) const;

### operator !=

bool operator != (
const C * ptr
) const;

### operator !=

bool operator != (
C * ptr
) const;

### operator !=

bool operator != (
std::nullptr_t ptr
) const;

### operator *

C & operator * ();

### operator *

const C & operator * () const;

### operator <

bool operator < (
const AutoPtr & ptr
) const;

### operator <

bool operator < (
const C * ptr
) const;

### operator <

bool operator < (
C * ptr
) const;

### operator <=

bool operator <= (
const AutoPtr & ptr
) const;

### operator <=

bool operator <= (
const C * ptr
) const;

### operator <=

bool operator <= (
C * ptr
) const;

### operator =

AutoPtr & operator = (
C * ptr
);

### operator =

AutoPtr & operator = (
const AutoPtr & ptr
);

### operator =

AutoPtr & operator = (
AutoPtr && ptr
) noexcept;

### operator =

template < class Other > AutoPtr & operator = (
const AutoPtr < Other > & ptr
);

### operator ==

bool operator == (
const AutoPtr & ptr
) const;

### operator ==

bool operator == (
const C * ptr
) const;

### operator ==

bool operator == (
C * ptr
) const;

### operator ==

bool operator == (
std::nullptr_t ptr
) const;

### operator >

bool operator > (
const AutoPtr & ptr
) const;

### operator >

bool operator > (
const C * ptr
) const;

### operator >

bool operator > (
C * ptr
) const;

### operator >=

bool operator >= (
const AutoPtr & ptr
) const;

### operator >=

bool operator >= (
const C * ptr
) const;

### operator >=

bool operator >= (
C * ptr
) const;

### operator C *

operator C * ();

### operator const C *

operator const C * () const;

### operator->

C * operator-> ();

### operator->

const C * operator-> () const;

### reset

void reset();

### reset

void reset(
C * ptr
);

### reset

void reset(
C * ptr,
bool shared
);

### reset

void reset(
const AutoPtr & ptr
);

### reset

template < class Other > void reset(
const AutoPtr < Other > & ptr
);

### swap

void swap(
AutoPtr & ptr
) noexcept;

### unsafeCast

template < class Other > AutoPtr < Other > unsafeCast() const;

Casts the AutoPtr via a static cast to the given type. Example: (assume class Sub: public Super)

    AutoPtr<Super> super(new Sub());
    AutoPtr<Sub> sub = super.unsafeCast<Sub>();
    poco_assert (sub.get());