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std::weak_ptr

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< cpp‎ | memory

 
 
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Gestión de memoria dinámica
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std::weak_ptr
Las funciones miembro
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weak_ptr::weak_ptr
weak_ptr::~weak_ptr
weak_ptr::operator=
Modificadores
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Modifiers
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weak_ptr::reset
weak_ptr::swap
Los observadores
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Observers
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weak_ptr::use_count
weak_ptr::expired
weak_ptr::lock
weak_ptr::owner_before
Terceros funciones
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Non-member functions
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std::swap
 
Defined in header <memory>
template< class T > class weak_ptr;
(desde C++11)
std::weak_ptr es un puntero inteligente que contiene un no propietario ("débil") referencia a un objeto que está gestionado por std::shared_ptr. Esto se debe convertir a std::shared_ptr con el fin de acceder el objeto referenciado .
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 modelos de propiedad temporal:. cuando un objeto se debe acceder sólo si existe, y puede ser eliminada en cualquier momento por otra persona, std::weak_ptr se utiliza para realizar el seguimiento del objeto, y se convierte en std::shared_ptr a asumir la propiedad temporal. std::shared_ptr Si el original se destruye en este momento, la vida útil del objeto se prorrogará hasta el std::shared_ptr temporal se destruye también .
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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Además, std::weak_ptr se utiliza para romper las referencias circulares de std::shared_ptr .
Original:
In addition, std::weak_ptr is used to break circular references of std::shared_ptr.
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Contenido

[editar] Tipos de miembros

Miembro de tipo
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Member type
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Definition
element_type T

[editar] Las funciones miembro

crea una nueva weak_ptr
Original:
creates a new weak_ptr
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(miembro público función) [edit]
destruye una weak_ptr
Original:
destroys a weak_ptr
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(miembro público función) [edit]
asigna el weak_ptr
Original:
assigns the weak_ptr
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(miembro público función) [edit]
Modificadores
Original:
Modifiers
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libera la posesión del objeto gestionado
Original:
releases the ownership of the managed object
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(miembro público función) [edit]
intercambia los objetos gestionados
Original:
swaps the managed objects
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(miembro público función) [edit]
Los observadores
Original:
Observers
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devuelve el número de objetos shared_ptr que gestionan el objeto
Original:
returns the number of shared_ptr objects that manage the object
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(miembro público función) [edit]
Comprueba si el objeto de referencia ya ha sido eliminado
Original:
checks whether the referenced object was already deleted
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(miembro público función) [edit]
crea una shared_ptr que gestiona el objeto referenciado
Original:
creates a shared_ptr that manages the referenced object
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(miembro público función) [edit]
ofrece propietario basado en pedidos de punteros débiles
Original:
provides owner-based ordering of weak pointers
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(miembro público función) [edit]

[editar] Terceros funciones

el algoritmo se especializa std::swap
Original:
specializes the std::swap algorithm
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(función de plantilla) [edit]

[editar] Ejemplo

cómo bloqueo se utiliza para asegurar la validez del puntero .
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 usage
	std::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