Library: Foundation
Package: Core
Header: Poco/SharedPtr.h
Description
SharedPtr is a "smart" pointer for classes implementing reference counting based garbage collection. SharedPtr is thus similar to AutoPtr. Unlike the AutoPtr template, which can only be used with classes that support reference counting, SharedPtr can be used with any class. For this to work, a SharedPtr manages a reference count for the object it manages.
SharedPtr works in the following way: If an SharedPtr 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 is initialized to one. If the SharedPtr is assigned another SharedPtr, the object's reference count is incremented by one. The destructor of SharedPtr decrements the object's reference count by one and deletes the object if the reference count reaches zero. SharedPtr supports dereferencing with both the -> and the * operator. An attempt to dereference a null SharedPtr results in a NullPointerException being thrown. SharedPtr also implements all relational operators and a cast operator in case dynamic casting of the encapsulated data types is required.
Member Summary
Member Functions: assign, cast, get, isNull, operator !, operator !=, operator *, operator <, operator <=, operator =, operator ==, operator >, operator >=, operator C *, operator const C *, operator->, referenceCount, reset, swap, unsafeCast
Types
Type
typedef C Type;
Constructors
SharedPtr 
SharedPtr();
SharedPtr
SharedPtr(
C * ptr
);
SharedPtr
template < class Other, class OtherRP > SharedPtr(
const SharedPtr < Other, RC, OtherRP > & ptr
);
SharedPtr
SharedPtr(
const SharedPtr & ptr
);
SharedPtr
SharedPtr(
SharedPtr && ptr
) noexcept;
Destructor
~SharedPtr
~SharedPtr();
Member Functions
assign
SharedPtr & assign(
C * ptr
);
assign
SharedPtr & assign(
const SharedPtr & ptr
);
assign
template < class Other, class OtherRP > SharedPtr & assign(
const SharedPtr < Other, RC, OtherRP > & ptr
);
cast
template < class Other > SharedPtr < Other, RC, RP > cast() const;
Casts the SharedPtr via a dynamic cast to the given type. Returns an SharedPtr containing NULL if the cast fails. Example: (assume class Sub: public Super)
SharedPtr<Super> super(new Sub()); SharedPtr<Sub> sub = super.cast<Sub>(); poco_assert (sub.get());
get
C * get();
get
const C * get() const;
isNull
bool isNull() const;
operator !
bool operator ! () const;
operator !=
bool operator != (
const SharedPtr & 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 SharedPtr & ptr
) const;
operator <
bool operator < (
const C * ptr
) const;
operator <
bool operator < (
C * ptr
) const;
operator <=
bool operator <= (
const SharedPtr & ptr
) const;
operator <=
bool operator <= (
const C * ptr
) const;
operator <=
bool operator <= (
C * ptr
) const;
operator =
SharedPtr & operator = (
C * ptr
);
operator =
SharedPtr & operator = (
const SharedPtr & ptr
);
operator =
SharedPtr & operator = (
SharedPtr && ptr
) noexcept;
operator =
template < class Other, class OtherRP > SharedPtr & operator = (
const SharedPtr < Other, RC, OtherRP > & ptr
);
operator ==
bool operator == (
const SharedPtr & 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 SharedPtr & ptr
) const;
operator >
bool operator > (
const C * ptr
) const;
operator >
bool operator > (
C * ptr
) const;
operator >=
bool operator >= (
const SharedPtr & 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;
referenceCount
int referenceCount() const;
reset
void reset();
reset
void reset(
C * ptr
);
reset
void reset(
const SharedPtr & ptr
);
reset
template < class Other, class OtherRP > void reset(
const SharedPtr < Other, RC, OtherRP > & ptr
);
swap
void swap(
SharedPtr & ptr
) noexcept;
unsafeCast
template < class Other > SharedPtr < Other, RC, RP > unsafeCast() const;
Casts the SharedPtr via a static cast to the given type. Example: (assume class Sub: public Super)
SharedPtr<Super> super(new Sub()); SharedPtr<Sub> sub = super.unsafeCast<Sub>(); poco_assert (sub.get());