fcppt::weak_ptr< Type, Deleter > Class Template Reference

Detailed Description

template<typename Type, typename Deleter = fcppt::default_deleter>
class fcppt::weak_ptr< Type, Deleter >

A weak reference to an object owned by a shared pointer.

A weak pointer contributes to the weak reference count of on object owned by shared pointers. The difference is that a weak pointer won't stop the object from being destructed. Such a weak pointer can be used to observe if there are any shared pointers left.

Template Parameters

Type	The type the weak pointer points to
Deleter	A deleter class that must be callable with a pointer to Type.

Public Types
using	impl_type = std::weak_ptr<Type>
	The type if the std::weak_ptr used to implement this class.
using	shared_ptr = fcppt::shared_ptr<Type, Deleter>
	The corresponding shared pointer class.
using	element_type = Type
	The element type, which is Type.
using	count_type
	The reference count type.

Public Member Functions
	weak_ptr ()
	Constructs an empty weak ptr.
template<typename Other >
	weak_ptr (fcppt::weak_ptr< Other, Deleter > const &ref)
	Constructs a weak_ptr from a compatible weak_ptr type.
template<typename Other >
	weak_ptr (fcppt::shared_ptr< Other, Deleter > const &ref)
	Constructs a weak_ptr from a compatible shared_ptr.
fcppt::optional::object< shared_ptr >	lock () const
	Returns a shared_ptr pointing to the shared object of this weak_ptr.
count_type	use_count () const noexcept
	The use count.
bool	expired () const noexcept
	Returns if the weak_ptr still points to a shared object.
void	swap (weak_ptr &other) noexcept
	Swaps the weak_ptr.
impl_type	std_ptr () const
	Returns the underlying std::weak_ptr object.

Member Typedef Documentation

count_type

template<typename Type , typename Deleter = fcppt::default_deleter>

using fcppt::weak_ptr< Type, Deleter >::count_type

Initial value:

 
      
      long

The reference count type.

element_type

template<typename Type , typename Deleter = fcppt::default_deleter>

using fcppt::weak_ptr< Type, Deleter >::element_type = Type

The element type, which is Type.

impl_type

template<typename Type , typename Deleter = fcppt::default_deleter>

using fcppt::weak_ptr< Type, Deleter >::impl_type = std::weak_ptr<Type>

The type if the std::weak_ptr used to implement this class.

shared_ptr

template<typename Type , typename Deleter = fcppt::default_deleter>

using fcppt::weak_ptr< Type, Deleter >::shared_ptr = fcppt::shared_ptr<Type, Deleter>

The corresponding shared pointer class.

Constructor & Destructor Documentation

weak_ptr() [1/3]

template<typename Type , typename Deleter = fcppt::default_deleter>

fcppt::weak_ptr< Type, Deleter >::weak_ptr

(

)

Constructs an empty weak ptr.

weak_ptr() [2/3]

template<typename Type , typename Deleter = fcppt::default_deleter>

template<typename Other >

fcppt::weak_ptr< Type, Deleter >::weak_ptr ( fcppt::weak_ptr< Other, Deleter > const & ref )

explicit

Constructs a weak_ptr from a compatible weak_ptr type.

Constructs a weak_ptr from the weak_ptr ref. This weak_ptr will belong to the same shared_ptrs as ref does.

Template Parameters

Other

A type, so that Other * is implicitly convertible to Type *

Parameters

ref	The weak_ptr to copy

weak_ptr() [3/3]

template<typename Type , typename Deleter = fcppt::default_deleter>

template<typename Other >

fcppt::weak_ptr< Type, Deleter >::weak_ptr ( fcppt::shared_ptr< Other, Deleter > const & ref )

explicit

Constructs a weak_ptr from a compatible shared_ptr.

Constructs a weak_ptr from the shared_ptr ref which will keep track of the shared count of the shared_ptr.

Template Parameters

Other

A type, so that Other * is implicitly convertible to Type *

Parameters

ref	The shared_ptr to monitor

Member Function Documentation

expired()

template<typename Type , typename Deleter = fcppt::default_deleter>

bool fcppt::weak_ptr< Type, Deleter >::expired ( ) const

nodiscardnoexcept

Returns if the weak_ptr still points to a shared object.

If this weak_ptr is empty, false will be returned. Otherwise if the shared count is still greater than zero, true will be returned.

lock()

template<typename Type , typename Deleter = fcppt::default_deleter>

fcppt::optional::object< shared_ptr > fcppt::weak_ptr< Type, Deleter >::lock ( ) const

nodiscard

Returns a shared_ptr pointing to the shared object of this weak_ptr.

If the shared object is still alive (which means that the reference count is still greater than zero), then a new shared_ptr also owning that object will be returned. If all shared_ptrs have been destroyed, then an empty optional will be returned.

std_ptr()

template<typename Type , typename Deleter = fcppt::default_deleter>

impl_type fcppt::weak_ptr< Type, Deleter >::std_ptr ( ) const

nodiscard

Returns the underlying std::weak_ptr object.

swap()

template<typename Type , typename Deleter = fcppt::default_deleter>

void fcppt::weak_ptr< Type, Deleter >::swap ( weak_ptr< Type, Deleter > & other )

noexcept

Swaps the weak_ptr.

Swaps the weak_ptr with other.

Parameters

other

The shared_ptr to swap with

use_count()

template<typename Type , typename Deleter = fcppt::default_deleter>

count_type fcppt::weak_ptr< Type, Deleter >::use_count ( ) const

nodiscardnoexcept

The use count.

If this weak_ptr is empty, zero will be returned. Otherwise the shared count of the shared object will be returned.

Note

This type is long because std::shared_ptr also uses long.