Varianti

    std::weak_ptr::weak_ptr

    Da cppreference.com.

    Questa pagina è stata tradotta in modo automatico dalla versione in ineglese della wiki usando Google Translate.

    La traduzione potrebbe contenere errori e termini strani. Muovi il puntatore sopra al testo per vedere la versione originale. Puoi aiutarci a correggere gli gli errori. Per ulteriori istruzioni clicca qui.

    Click here for the English version of this page

    <metanoindex/>

     
    C++
     
    Utilità libreria
    Tipo di supporto (basic types, RTTI, type traits)
    Gestione della memoria dinamica
    La gestione degli errori
    Programma di utilità
    Funzioni variadic
    Data e ora
    Funzione oggetti
    initializer_list(C++11)
    bitset
    hash(C++11)
    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>=
    Coppie e tuple
    Original:
    Pairs and tuples
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
    pair
    tuple(C++11)
    piecewise_construct_t(C++11)
    piecewise_construct(C++11)
    Swap, in avanti e spostare
    Original:
    Swap, forward and move
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
    swap
    forward(C++11)
    move(C++11)
    move_if_noexcept(C++11)
    declval(C++11)
     
    Gestione della memoria dinamica
    Basso livello di gestione della memoria
    Allocatori
    Original:
    Allocators
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
    allocator
    allocator_traits(C++11)
    allocator_arg_t(C++11)
    allocator_arg(C++11)
    uses_allocator(C++11)
    scoped_allocator_adaptor(C++11)
    Non inizializzata stoccaggio
    Original:
    Uninitialized storage
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
    uninitialized_copy
    uninitialized_copy_n(C++11)
    uninitialized_fill
    uninitialized_fill_n
    raw_storage_iterator
    get_temporary_buffer
    return_temporary_buffer
    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)
    default_delete(C++11)
    Garbage collection supporto
    Original:
    Garbage collection support
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
    declare_reachable(C++11)
    undeclare_reachable(C++11)
    declare_no_pointers(C++11)
    undeclare_no_pointers(C++11)
    pointer_safety(C++11)
    get_pointer_safety(C++11)
    Varie
    Original:
    Miscellaneous
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
    pointer_traits(C++11)
    addressof(C++11)
    align(C++11)
    C Library
    Original:
    C Library
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.
     
    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
     
    <tbody> </tbody>
    constexpr weak_ptr();
    		 (1) (dal C++11)
    weak_ptr( const weak_ptr& r );
    		 (2) (dal C++11)
    template< class Y > weak_ptr( const weak_ptr<Y>& r );
    		 (2) (dal C++11)
    template< class Y > weak_ptr( const std::shared_ptr<Y>& r );
    		 (2) (dal C++11)
    Costruisce weak_ptr nuova che condivide potenzialmente un oggetto con r.
    Original:
    Constructs new weak_ptr that potentially shares an object with r.
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.

    1)

    Costruttore di default. Costruisce weak_ptr vuoto.
    Original:
    Default constructor. Constructs empty weak_ptr.
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.

    2)

    Costruisce weak_ptr nuova che condivide un oggetto gestito da r. Se r gestisce nessun oggetto, *this gestisce nessun oggetto troppo. Gli overload basate su modelli non prende parte alla risoluzione di sovraccarico a meno Y* la conversione implicita in T*.
    Original:
    Constructs new weak_ptr which shares an object managed by r. If r manages no object, *this manages no object too. The templated overloads don't participate in the overload resolution unless Y* is implicitly convertible to T*.
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.

    Parametri

    r -
    un std::shared_ptr o std::weak_ptr che verrà visualizzato da questo std::weak_ptr
    Original:
    a std::shared_ptr or std::weak_ptr that will be viewed by this std::weak_ptr
    The text has been machine-translated via Google Translate.
    You can help to correct and verify the translation. Click here for instructions.

    Eccezioni

    noexcept specification:  
    <tbody> </tbody>
    noexcept
      (dal C++11)

    Esempio

    #include <memory>
#include <iostream>

struct Foo {};

int main()
{
   std::weak_ptr<Foo> w_ptr;

   {
      auto ptr = std::make_shared<Foo>();
      w_ptr = ptr;
      std::cout << "w_ptr.use_count() inside scope: " << w_ptr.use_count() << '\n';
   }

   std::cout << "w_ptr.use_count() out of scope: " << w_ptr.use_count() << '\n';
}

    Output: 

    w_ptr.use_count() inside scope: 1
w_ptr.use_count() out of scope: 0

    Vedi anche
    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) [modifica]