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Internal/Contributor docs for the Qt SDK. Note: These are NOT official API docs; those are found at https://doc.qt.io/
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QWeakPointer< T > Class Template Reference

\inmodule QtCore More...

#include <qsharedpointer_impl.h>

+ Collaboration diagram for QWeakPointer< T >:

Public Types

typedef T element_type
 
typedef T value_type
 
typedef value_typepointer
 
typedef const value_typeconst_pointer
 
typedef value_typereference
 
typedef const value_typeconst_reference
 
typedef qptrdiff difference_type
 

Public Member Functions

bool isNull () const noexcept
 Returns true if this object refers to \nullptr.
 
 operator bool () const noexcept
 Returns true if the contained pointer is not \nullptr.
 
bool operator! () const noexcept
 Returns true if this object refers to \nullptr.
 
Q_NODISCARD_CTOR constexpr QWeakPointer () noexcept
 
 ~QWeakPointer ()
 Destroys this QWeakPointer object.
 
Q_NODISCARD_CTOR QWeakPointer (const QWeakPointer &other) noexcept
 Creates a QWeakPointer that holds a weak reference to the pointer referenced by other.
 
Q_NODISCARD_CTOR QWeakPointer (QWeakPointer &&other) noexcept
 
template<class X, IfCompatible< X > = true, IfNotVirtualBase< X > = true>
Q_NODISCARD_CTOR QWeakPointer (QWeakPointer< X > &&other) noexcept
 
template<class X, IfCompatible< X > = true, IfVirtualBase< X > = true>
Q_NODISCARD_CTOR QWeakPointer (QWeakPointer< X > &&other) noexcept
 
template<class X, IfCompatible< X > = true>
QWeakPointeroperator= (QWeakPointer< X > &&other) noexcept
 
QWeakPointeroperator= (const QWeakPointer &other) noexcept
 Makes this object share other's pointer.
 
void swap (QWeakPointer &other) noexcept
 
Q_NODISCARD_CTOR QWeakPointer (const QSharedPointer< T > &o)
 Creates a QWeakPointer that holds a weak reference to the pointer referenced by other.
 
QWeakPointeroperator= (const QSharedPointer< T > &o)
 Makes this object share other's pointer.
 
template<class X, IfCompatible< X > = true>
Q_NODISCARD_CTOR QWeakPointer (const QWeakPointer< X > &o)
 
template<class X, IfCompatible< X > = true>
QWeakPointeroperator= (const QWeakPointer< X > &o)
 
template<class X, IfCompatible< X > = true>
Q_NODISCARD_CTOR QWeakPointer (const QSharedPointer< X > &o)
 
template<class X, IfCompatible< X > = true>
QWeakPointeroperator= (const QSharedPointer< X > &o)
 
void clear ()
 Clears this QWeakPointer object, dropping the reference that it may have had to the pointer.
 
QSharedPointer< T > toStrongRef () const
 Promotes this weak reference to a strong one and returns a QSharedPointer object holding that reference.
 
QSharedPointer< T > lock () const
 
template<class X>
bool operator== (const QWeakPointer< X > &o) const noexcept
 
template<class X>
bool operator!= (const QWeakPointer< X > &o) const noexcept
 
template<class X>
bool operator== (const QSharedPointer< X > &o) const noexcept
 
template<class X>
bool operator!= (const QSharedPointer< X > &o) const noexcept
 
template<typename X>
bool owner_before (const QWeakPointer< X > &other) const noexcept
 
template<typename X>
bool owner_before (const QSharedPointer< X > &other) const noexcept
 
template<typename X>
bool owner_equal (const QWeakPointer< X > &other) const noexcept
 
template<typename X>
bool owner_equal (const QSharedPointer< X > &other) const noexcept
 
size_t owner_hash () const noexcept
 

Friends

struct QtPrivate::EnableInternalData
 
template<class X>
class QSharedPointer
 
template<class X>
class QWeakPointer
 Creates a QWeakPointer that points to nothing.
 
template<class X>
class QPointer
 
template<typename X>
bool operator== (const QSharedPointer< X > &p1, const QWeakPointer &p2) noexcept
 
template<typename X>
bool operator!= (const QSharedPointer< X > &p1, const QWeakPointer &p2) noexcept
 
bool operator== (const QWeakPointer &p, std::nullptr_t)
 
bool operator== (std::nullptr_t, const QWeakPointer &p)
 
bool operator!= (const QWeakPointer &p, std::nullptr_t)
 
bool operator!= (std::nullptr_t, const QWeakPointer &p)
 

Related Symbols

(Note that these are not member symbols.)

template< class T, class X > bool operator== (const QSharedPointer< T > &ptr1, const QWeakPointer< X > &ptr2)
 Returns true if ptr1 and ptr2 refer to the same pointer.
 
template< class T, class X > bool operator!= (const QSharedPointer< T > &ptr1, const QWeakPointer< X > &ptr2)
 Returns true if ptr1 and ptr2 refer to distinct pointers.
 
template< class T, class X > bool operator== (const QWeakPointer< T > &ptr1, const QSharedPointer< X > &ptr2)
 Returns true if ptr1 and ptr2 refer to the same pointer.
 
template< class T, class X > bool operator!= (const QWeakPointer< T > &ptr1, const QSharedPointer< X > &ptr2)
 Returns true if ptr1 and ptr2 refer to distinct pointers.
 
template< class X, class T > QSharedPointer< XqSharedPointerCast (const QWeakPointer< T > &other)
 Returns a shared pointer to the pointer held by other, cast to type \tt X.
 
template< class X, class T > QSharedPointer< XqSharedPointerDynamicCast (const QWeakPointer< T > &src)
 Returns a shared pointer to the pointer held by src, using a dynamic cast to type \tt X to obtain an internal pointer of the appropriate type.
 
template< class X, class T > QSharedPointer< XqSharedPointerConstCast (const QWeakPointer< T > &src)
 Returns a shared pointer to the pointer held by src, cast to type \tt X.
 
template< class X, class T > QSharedPointer< XqSharedPointerObjectCast (const QWeakPointer< T > &src)
 The qSharedPointerObjectCast function is for casting a shared pointer.
 
template< class X, class T > QWeakPointer< XqWeakPointerCast (const QWeakPointer< T > &src)
 Returns a weak pointer to the pointer held by src, cast to type \tt X.
 

Detailed Description

template<class T>
class QWeakPointer< T >

\inmodule QtCore

The QWeakPointer class holds a weak reference to a shared pointer.

Since
4.5 \reentrant

The QWeakPointer is an automatic weak reference to a pointer in C++. It cannot be used to dereference the pointer directly, but it can be used to verify if the pointer has been deleted or not in another context.

QWeakPointer objects can only be created by assignment from a QSharedPointer.

It's important to note that QWeakPointer provides no automatic casting operators to prevent mistakes from happening. Even though QWeakPointer tracks a pointer, it should not be considered a pointer itself, since it doesn't guarantee that the pointed object remains valid.

Therefore, to access the pointer that QWeakPointer is tracking, you must first promote it to QSharedPointer and verify if the resulting object is null or not. QSharedPointer guarantees that the object isn't deleted, so if you obtain a non-null object, you may use the pointer. See QWeakPointer::toStrongRef() for an example.

\omit

Definition at line 591 of file qsharedpointer_impl.h.

Member Typedef Documentation

◆ const_pointer

template<class T>
typedef const value_type* QWeakPointer< T >::const_pointer

Definition at line 607 of file qsharedpointer_impl.h.

◆ const_reference

template<class T>
typedef const value_type& QWeakPointer< T >::const_reference

Definition at line 609 of file qsharedpointer_impl.h.

◆ difference_type

template<class T>
typedef qptrdiff QWeakPointer< T >::difference_type

Definition at line 610 of file qsharedpointer_impl.h.

◆ element_type

template<class T>
typedef T QWeakPointer< T >::element_type

Definition at line 604 of file qsharedpointer_impl.h.

◆ pointer

template<class T>
typedef value_type* QWeakPointer< T >::pointer

Definition at line 606 of file qsharedpointer_impl.h.

◆ reference

template<class T>
typedef value_type& QWeakPointer< T >::reference

Definition at line 608 of file qsharedpointer_impl.h.

◆ value_type

template<class T>
typedef T QWeakPointer< T >::value_type

Definition at line 605 of file qsharedpointer_impl.h.

Constructor & Destructor Documentation

◆ QWeakPointer() [1/8]

template<class T>
Q_NODISCARD_CTOR constexpr QWeakPointer< T >::QWeakPointer ( )
inlineconstexprnoexcept

Definition at line 617 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ ~QWeakPointer()

template<class T>
QWeakPointer< T >::~QWeakPointer ( )
inline

Destroys this QWeakPointer object.

The pointer referenced by this object will not be deleted.

Definition at line 618 of file qsharedpointer_impl.h.

◆ QWeakPointer() [2/8]

template<class T>
Q_NODISCARD_CTOR QWeakPointer< T >::QWeakPointer ( const QWeakPointer< T > & other)
inlinenoexcept

Creates a QWeakPointer that holds a weak reference to the pointer referenced by other.

If \tt T is a derived type of the template parameter of this class, QWeakPointer will perform an automatic cast. Otherwise, you will get a compiler error.

Definition at line 621 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ QWeakPointer() [3/8]

template<class T>
Q_NODISCARD_CTOR QWeakPointer< T >::QWeakPointer ( QWeakPointer< T > && other)
inlinenoexcept

Definition at line 624 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ QWeakPointer() [4/8]

template<class T>
template<class X, IfCompatible< X > = true, IfNotVirtualBase< X > = true>
Q_NODISCARD_CTOR QWeakPointer< T >::QWeakPointer ( QWeakPointer< X > && other)
inlinenoexcept

Definition at line 634 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ QWeakPointer() [5/8]

template<class T>
template<class X, IfCompatible< X > = true, IfVirtualBase< X > = true>
Q_NODISCARD_CTOR QWeakPointer< T >::QWeakPointer ( QWeakPointer< X > && other)
inlinenoexcept

Definition at line 642 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ QWeakPointer() [6/8]

template<class T>
Q_NODISCARD_CTOR QWeakPointer< T >::QWeakPointer ( const QSharedPointer< T > & other)
inline

Creates a QWeakPointer that holds a weak reference to the pointer referenced by other.

If \tt T is a derived type of the template parameter of this class, QWeakPointer will perform an automatic cast. Otherwise, you will get a compiler error.

Definition at line 671 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ QWeakPointer() [7/8]

template<class T>
template<class X, IfCompatible< X > = true>
Q_NODISCARD_CTOR QWeakPointer< T >::QWeakPointer ( const QWeakPointer< X > & o)
inline

Definition at line 681 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ QWeakPointer() [8/8]

template<class T>
template<class X, IfCompatible< X > = true>
Q_NODISCARD_CTOR QWeakPointer< T >::QWeakPointer ( const QSharedPointer< X > & o)
inline

Definition at line 695 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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Member Function Documentation

◆ clear()

template<class T>
void QWeakPointer< T >::clear ( )
inline

Clears this QWeakPointer object, dropping the reference that it may have had to the pointer.

Definition at line 705 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ isNull()

template<class T>
bool QWeakPointer< T >::isNull ( ) const
inlinenoexcept

Returns true if this object refers to \nullptr.

Note that, due to the nature of weak references, the pointer that QWeakPointer references can become \nullptr at any moment, so the value returned from this function can change from false to true from one call to the next.

Definition at line 612 of file qsharedpointer_impl.h.

Referenced by operator bool(), and operator!().

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◆ lock()

template<class T>
QSharedPointer< T > QWeakPointer< T >::lock ( ) const
inlinenodiscard
Since
5.4

Same as toStrongRef().

This function is provided for API compatibility with std::weak_ptr.

Definition at line 709 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ operator bool()

template<class T>
QWeakPointer< T >::operator bool ( ) const
inlineexplicitnoexcept

Returns true if the contained pointer is not \nullptr.

This function is suitable for use in \tt if-constructs, like:

if (weakref) { ... }

Note that, due to the nature of weak references, the pointer that QWeakPointer references can become \nullptr at any moment, so the value returned from this function can change from true to false from one call to the next.

See also
isNull()

Definition at line 613 of file qsharedpointer_impl.h.

References isNull().

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◆ operator!()

template<class T>
bool QWeakPointer< T >::operator! ( ) const
inlinenoexcept

Returns true if this object refers to \nullptr.

This function is suitable for use in \tt if-constructs, like:

if (!weakref) { ... }

Note that, due to the nature of weak references, the pointer that QWeakPointer references can become \nullptr at any moment, so the value returned from this function can change from false to true from one call to the next.

See also
isNull()

Definition at line 614 of file qsharedpointer_impl.h.

References isNull().

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◆ operator!=() [1/2]

template<class T>
template<class X>
bool QWeakPointer< T >::operator!= ( const QSharedPointer< X > & o) const
inlinenoexcept

Definition at line 724 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ operator!=() [2/2]

template<class T>
template<class X>
bool QWeakPointer< T >::operator!= ( const QWeakPointer< X > & o) const
inlinenoexcept

Definition at line 716 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ operator=() [1/5]

template<class T>
QWeakPointer & QWeakPointer< T >::operator= ( const QSharedPointer< T > & other)
inline

Makes this object share other's pointer.

The current pointer reference is discarded but is not deleted.

If \tt T is a derived type of the template parameter of this class, QWeakPointer will perform an automatic cast. Otherwise, you will get a compiler error.

Definition at line 673 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ operator=() [2/5]

template<class T>
template<class X, IfCompatible< X > = true>
QWeakPointer & QWeakPointer< T >::operator= ( const QSharedPointer< X > & o)
inline

Definition at line 699 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ operator=() [3/5]

template<class T>
QWeakPointer & QWeakPointer< T >::operator= ( const QWeakPointer< T > & other)
inlinenoexcept

Makes this object share other's pointer.

The current pointer reference is discarded but is not deleted.

If \tt T is a derived type of the template parameter of this class, QWeakPointer will perform an automatic cast. Otherwise, you will get a compiler error.

Definition at line 657 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ operator=() [4/5]

template<class T>
template<class X, IfCompatible< X > = true>
QWeakPointer & QWeakPointer< T >::operator= ( const QWeakPointer< X > & o)
inline

Definition at line 685 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ operator=() [5/5]

template<class T>
template<class X, IfCompatible< X > = true>
QWeakPointer & QWeakPointer< T >::operator= ( QWeakPointer< X > && other)
inlinenoexcept

Definition at line 650 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ operator==() [1/2]

template<class T>
template<class X>
bool QWeakPointer< T >::operator== ( const QSharedPointer< X > & o) const
inlinenoexcept

Definition at line 720 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ operator==() [2/2]

template<class T>
template<class X>
bool QWeakPointer< T >::operator== ( const QWeakPointer< X > & o) const
inlinenoexcept

Definition at line 712 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ owner_before() [1/2]

template<class T>
template<typename X>
bool QWeakPointer< T >::owner_before ( const QSharedPointer< X > & other) const
inlinenoexcept

Definition at line 747 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ owner_before() [2/2]

template<class T>
template<typename X>
bool QWeakPointer< T >::owner_before ( const QWeakPointer< X > & other) const
inlinenoexcept
Since
6.7

Returns true if and only if this smart pointer precedes other in an implementation-defined owner-based ordering. The ordering is such that two smart pointers are considered equivalent if they are both empty or if they both own the same object (even if their apparent type and pointer are different).

See also
owner_equal

Definition at line 744 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ owner_equal() [1/2]

template<class T>
template<typename X>
bool QWeakPointer< T >::owner_equal ( const QSharedPointer< X > & other) const
inlinenoexcept

Definition at line 754 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ owner_equal() [2/2]

template<class T>
template<typename X>
bool QWeakPointer< T >::owner_equal ( const QWeakPointer< X > & other) const
inlinenoexcept
Since
6.7

Returns true if and only if this smart pointer and other share ownership.

See also
owner_before, owner_hash

Definition at line 751 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ owner_hash()

template<class T>
size_t QWeakPointer< T >::owner_hash ( ) const
inlinenoexcept
Since
6.7

Returns a owner-based hash value for this smart pointer object. Smart pointers that compare equal (as per {owner_equal}) will have an identical owner-based hash.

See also
owner_equal

Definition at line 757 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ swap()

template<class T>
void QWeakPointer< T >::swap ( QWeakPointer< T > & other)
inlinenoexcept
Since
5.4 \memberswap{weak pointer instance}

Definition at line 664 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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◆ toStrongRef()

template<class T>
QSharedPointer< T > QWeakPointer< T >::toStrongRef ( ) const
inlinenodiscard

Promotes this weak reference to a strong one and returns a QSharedPointer object holding that reference.

When promoting to QSharedPointer, this function verifies if the object has been deleted already or not. If it hasn't, this function increases the reference count to the shared object, thus ensuring that it will not get deleted.

Since this function can fail to obtain a valid strong reference to the shared object, you should always verify if the conversion succeeded, by calling QSharedPointer::isNull() on the returned object.

For example, the following code promotes a QWeakPointer that was held to a strong reference and, if it succeeded, it prints the value of the integer that was held:

// ...
if (strong)
qDebug() << "The value is:" << *strong;
else
qDebug() << "The value has already been deleted";
See also
QSharedPointer::QSharedPointer()

Definition at line 707 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

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Friends And Related Symbol Documentation

◆ QWeakPointer

template<class T>
template<class X>
friend class QWeakPointer
friend

Creates a QWeakPointer that points to nothing.

Definition at line 763 of file qsharedpointer_impl.h.

◆ operator!=() [1/5]

template<class T>
template< class T, class X > bool operator!= ( const QSharedPointer< T > & ptr1,
const QWeakPointer< X > & ptr2 )
related

Returns true if ptr1 and ptr2 refer to distinct pointers.

If ptr2's template parameter is different from ptr1's, QSharedPointer will attempt to perform an automatic \tt static_cast to ensure that the pointers being compared are equal. If ptr2's template parameter is not a base or a derived type from ptr1's, you will get a compiler error.

◆ operator!= [2/5]

template<class T>
template<typename X>
bool operator!= ( const QSharedPointer< X > & p1,
const QWeakPointer< T > & p2 )
friend

Definition at line 731 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

◆ operator!= [3/5]

template<class T>
bool operator!= ( const QWeakPointer< T > & p,
std::nullptr_t  )
friend
Since
5.8

Returns true if lhs refers to a valid (i.e. non-null) pointer.

See also
QWeakPointer::isNull()

Definition at line 738 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

◆ operator!=() [4/5]

template<class T>
template< class T, class X > bool operator!= ( const QWeakPointer< T > & ptr1,
const QSharedPointer< X > & ptr2 )
related

Returns true if ptr1 and ptr2 refer to distinct pointers.

If ptr2's template parameter is different from ptr1's, QSharedPointer will attempt to perform an automatic \tt static_cast to ensure that the pointers being compared are equal. If ptr2's template parameter is not a base or a derived type from ptr1's, you will get a compiler error.

◆ operator!= [5/5]

template<class T>
bool operator!= ( std::nullptr_t ,
const QWeakPointer< T > & p )
friend
Since
5.8

Returns true if rhs refers to a valid (i.e. non-null) pointer.

See also
QWeakPointer::isNull()

Definition at line 740 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

◆ operator==() [1/5]

template<class T>
template< class T, class X > bool operator== ( const QSharedPointer< T > & ptr1,
const QWeakPointer< X > & ptr2 )
related

Returns true if ptr1 and ptr2 refer to the same pointer.

If ptr2's template parameter is different from ptr1's, QSharedPointer will attempt to perform an automatic \tt static_cast to ensure that the pointers being compared are equal. If ptr2's template parameter is not a base or a derived type from ptr1's, you will get a compiler error.

◆ operator== [2/5]

template<class T>
template<typename X>
bool operator== ( const QSharedPointer< X > & p1,
const QWeakPointer< T > & p2 )
friend

Definition at line 728 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

◆ operator== [3/5]

template<class T>
bool operator== ( const QWeakPointer< T > & p,
std::nullptr_t  )
friend
Since
5.8

Returns true if lhs refers to \nullptr.

See also
QWeakPointer::isNull()

Definition at line 734 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

◆ operator==() [4/5]

template<class T>
template< class T, class X > bool operator== ( const QWeakPointer< T > & ptr1,
const QSharedPointer< X > & ptr2 )
related

Returns true if ptr1 and ptr2 refer to the same pointer.

If ptr2's template parameter is different from ptr1's, QSharedPointer will attempt to perform an automatic \tt static_cast to ensure that the pointers being compared are equal. If ptr2's template parameter is not a base or a derived type from ptr1's, you will get a compiler error.

◆ operator== [5/5]

template<class T>
bool operator== ( std::nullptr_t ,
const QWeakPointer< T > & p )
friend
Since
5.8

Returns true if rhs refers to \nullptr.

See also
QWeakPointer::isNull()

Definition at line 736 of file qsharedpointer_impl.h.

References QSharedPointer< T >::QWeakPointer.

◆ QPointer

template<class T>
template<class X>
friend class QPointer
friend

Definition at line 764 of file qsharedpointer_impl.h.

◆ QSharedPointer

template<class T>
template<class X>
friend class QSharedPointer
friend

Definition at line 762 of file qsharedpointer_impl.h.

◆ qSharedPointerCast()

template<class T>
template< class X, class T > QSharedPointer< X > qSharedPointerCast ( const QWeakPointer< T > & other)
related

Returns a shared pointer to the pointer held by other, cast to type \tt X.

The types \tt T and \tt X must belong to one hierarchy for the \tt static_cast to succeed.

The other object is converted first to a strong reference. If that conversion fails (because the object it's pointing to has already been deleted), this function returns a null QSharedPointer.

Note that \tt X must have the same cv-qualifiers (\tt const and \tt volatile) that \tt T has, or the code will fail to compile. Use qSharedPointerConstCast to cast away the constness.

See also
QWeakPointer::toStrongRef(), qSharedPointerDynamicCast(), qSharedPointerConstCast()

Definition at line 911 of file qsharedpointer_impl.h.

◆ qSharedPointerConstCast()

template<class T>
template< class X, class T > QSharedPointer< X > qSharedPointerConstCast ( const QWeakPointer< T > & src)
related

Returns a shared pointer to the pointer held by src, cast to type \tt X.

The types \tt T and \tt X must belong to one hierarchy for the \tt const_cast to succeed. The \tt const and \tt volatile differences between \tt T and \tt X are ignored.

The src object is converted first to a strong reference. If that conversion fails (because the object it's pointing to has already been deleted), this function returns a null QSharedPointer.

See also
QWeakPointer::toStrongRef(), qSharedPointerCast(), qSharedPointerDynamicCast()

Definition at line 951 of file qsharedpointer_impl.h.

◆ qSharedPointerDynamicCast()

template<class T>
template< class X, class T > QSharedPointer< X > qSharedPointerDynamicCast ( const QWeakPointer< T > & src)
related

Returns a shared pointer to the pointer held by src, using a dynamic cast to type \tt X to obtain an internal pointer of the appropriate type.

If the \tt dynamic_cast fails, the object returned will be null.

The src object is converted first to a strong reference. If that conversion fails (because the object it's pointing to has already been deleted), this function also returns a null QSharedPointer.

Note that \tt X must have the same cv-qualifiers (\tt const and \tt volatile) that \tt T has, or the code will fail to compile. Use qSharedPointerConstCast to cast away the constness.

See also
QWeakPointer::toStrongRef(), qSharedPointerCast(), qSharedPointerConstCast()

Definition at line 933 of file qsharedpointer_impl.h.

◆ qSharedPointerObjectCast()

template<class T>
template< class X, class T > QSharedPointer< X > qSharedPointerObjectCast ( const QWeakPointer< T > & src)
related

The qSharedPointerObjectCast function is for casting a shared pointer.

Since
4.6

Returns a shared pointer to the pointer held by src, using a \l qobject_cast() to type \tt X to obtain an internal pointer of the appropriate type. If the \tt qobject_cast fails, the object returned will be null.

The src object is converted first to a strong reference. If that conversion fails (because the object it's pointing to has already been deleted), this function also returns a null QSharedPointer.

Note that \tt X must have the same cv-qualifiers (\tt const and \tt volatile) that \tt T has, or the code will fail to compile. Use qSharedPointerConstCast to cast away the constness.

See also
QWeakPointer::toStrongRef(), qSharedPointerCast(), qSharedPointerConstCast()

Definition at line 981 of file qsharedpointer_impl.h.

◆ QtPrivate::EnableInternalData

template<class T>
friend struct QtPrivate::EnableInternalData
friend

Definition at line 761 of file qsharedpointer_impl.h.

◆ qWeakPointerCast()

template<class T>
template< class X, class T > QWeakPointer< X > qWeakPointerCast ( const QWeakPointer< T > & src)
related

Returns a weak pointer to the pointer held by src, cast to type \tt X.

The types \tt T and \tt X must belong to one hierarchy for the \tt static_cast to succeed.

Note that \tt X must have the same cv-qualifiers (\tt const and \tt volatile) that \tt T has, or the code will fail to compile. Use qSharedPointerConstCast to cast away the constness.


The documentation for this class was generated from the following files: