std::weak_ptr

 

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Gli operatori relazionali Original: Relational operators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

rel_ops::operator!= rel_ops::operator> rel_ops::operator<= rel_ops::operator>=

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swap

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Gestione della memoria dinamica

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Puntatori intelligenti Original: Smart pointers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
unique_ptr (C++11)
shared_ptr (C++11)
weak_ptr (C++11)
auto_ptr (deprecato)
owner_less (C++11)
enable_shared_from_this (C++11)
bad_weak_ptr (C++11)
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std::weak_ptr

Membri funzioni Original: Member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

weak_ptr::weak_ptr

weak_ptr::~weak_ptr

weak_ptr::operator=

Modificatori Original: Modifiers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

weak_ptr::reset

weak_ptr::swap

Osservatori Original: Observers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

weak_ptr::use_count

weak_ptr::expired

weak_ptr::lock

weak_ptr::owner_before

Non membri funzioni Original: Non-member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

std::swap

 

Elemento definito nell'header <memory>
template<class T >class weak_ptr;		(dal C++11)

std::weak_ptr è un puntatore intelligente che contiene un non proprietario ("debole"), riferimento a un oggetto gestito da std::shared_ptr. Deve essere convertito in std::shared_ptr per accedere l'oggetto di riferimento.

Original:

std::weak_ptr is a smart pointer that holds a non-owning ("weak") reference to an object that is managed by std::shared_ptr. It must be converted to std::shared_ptr in order to access the referenced object.

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std::weak_ptr modelli temporanea di proprietà:. quando un oggetto ha bisogno di essere accessibile solo se esiste, e può essere cancellato in qualsiasi momento da un altro utente, std::weak_ptr viene utilizzato per monitorare l'oggetto, ed è convertito al std::shared_ptr di assumere proprietà temporanea. Se il std::shared_ptr originale viene distrutto in questo momento, la vita dell'oggetto è prorogato fino al std::shared_ptr temporaneo si distrugge anche la.

Original:

std::weak_ptr models temporary ownership: when an object needs to be accessed only if it exists, and it may be deleted at any time by someone else, std::weak_ptr is used to track the object, and it is converted to std::shared_ptr to assume temporary ownership. If the original std::shared_ptr is destroyed at this time, the object's lifetime is extended until the temporary std::shared_ptr is destroyed as well.

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Inoltre, std::weak_ptr viene utilizzato per interrompere i riferimenti circolari di std::shared_ptr.

Original:

In addition, std::weak_ptr is used to break circular references of std::shared_ptr.

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Membri tipi

Membro tipo Original: Member type The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.	Definition
element_type	T

Membri funzioni

(costruttore)	crea un nuovo weak_ptr Original: creates a new weak_ptr The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico)
(destructor)	distrugge un weak_ptr Original: destroys a weak_ptr The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico)
operator=	assegna il weak_ptr Original: assigns the weak_ptr The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico)
Modificatori Original: Modifiers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
reset	rilascia la proprietà dell'oggetto gestito Original: releases the ownership of the managed object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico)
swap	swap gli oggetti gestiti Original: swaps the managed objects The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico)
Osservatori Original: Observers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
use_count	restituisce il numero di oggetti shared_ptr che gestiscono l'oggetto Original: returns the number of shared_ptr objects that manage the object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico)
expired	Verifica se l'oggetto di riferimento è già stato cancellato Original: checks whether the referenced object was already deleted The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico)
lock	crea un shared_ptr che gestisce l'oggetto indicato Original: creates a shared_ptr that manages the referenced object The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico)
owner_before	fornisce proprietario basato ordinamento di puntatori deboli Original: provides owner-based ordering of weak pointers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico)

Non membri funzioni

std::swap(std::weak_ptr) (C++11)	specializzata l'algoritmo std::swap Original: specializes the std::swap algorithm The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (funzione di modello)

Esempio

Dimostra come blocco viene utilizzato per garantire la validità del puntatore .

Original:

Demonstrates how lock is used to ensure validity of the pointer.

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#include <iostream>#include <memory>   std::weak_ptr<int> gw;   void f(){if(auto spt = gw.lock()){// Has to be copied into a shared_ptr before usagestd::cout<<*spt <<"\n";}else{std::cout<<"gw is expired\n";}}   int main(){{auto sp =std::make_shared<int>(42); gw = sp;   f();}   f();}

Output:

42 gw is expired