std::weak_ptr

 

C++

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std::weak_ptr

Las funciones miembro 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=

Modificadores 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

Los observadores 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

Terceros funciones 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

 

Definido en el archivo de encabezado <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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Tipos de miembros

Miembro de 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

Las funciones miembro

(constructor)	crea una nueva 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. (función miembro pública)
(destructor)	destruye una 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. (función miembro pública)
operator=	asigna el 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. (función miembro pública)
Modificadores 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	libera la posesión del objeto gestionado 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. (función miembro pública)
swap	intercambia los objetos gestionados 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. (función miembro pública)
Los observadores 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	devuelve el número de objetos shared_ptr que gestionan el objeto 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. (función miembro pública)
expired	Comprueba si el objeto de referencia ya ha sido eliminado 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. (función miembro pública)
lock	crea una shared_ptr que gestiona el objeto referenciado 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. (función miembro pública)
owner_before	ofrece propietario basado en pedidos de punteros débiles 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. (función miembro pública)

Terceros funciones

std::swap(std::weak_ptr) (C++11)

Especializa el algoritmo std::swap. (plantilla de función)

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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Ejecuta este código

#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();
}

Salida:

42
gw is expired