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std::weak_ptr::expired

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< cpp‎ | memory‎ | weak ptr

 
 
Utilidades de la biblioteca
Escriba apoyo (basic types, RTTI, type traits)
Gestión de memoria dinámica
Gestión de errores
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Funciones variadic
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Objetos Function
(C++11)
Operadores relacionales
Original:
Relational operators
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Pares y tuplas
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Pairs and tuples
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(C++11)
Cambiar, hacia adelante y mover
Original:
Swap, forward and move
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(C++11)
(C++11)
(C++11)
 
Gestión de memoria dinámica
Bajo la gestión de memoria de nivel
Los asignadores
Original:
Allocators
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Inicializar el almacenamiento
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Uninitialized storage
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Punteros inteligentes
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Smart pointers
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(C++11)
(C++11)
(C++11)
(obsoleto)
(C++11)
Garbage soporte colección
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Garbage collection support
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Varios
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Miscellaneous
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(C++11)
(C++11)
C Library
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C Library
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std::weak_ptr
Las funciones miembro
Original:
Member functions
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Modificadores
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Modifiers
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Los observadores
Original:
Observers
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weak_ptr::expired
Terceros funciones
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Non-member functions
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bool expired() const;
(desde C++11)
Comprueba si el objeto administrado ya se ha eliminado. Equivalente a use_count() == 0 .
Original:
Checks whether the managed object has already been deleted. Equivalent to use_count() == 0.
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Contenido

[editar] Parámetros

(Ninguno)
Original:
(none)
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[editar] Valor de retorno

true si el objeto administrado ya ha sido eliminado, por lo demás false .
Original:
true if the managed object has already been deleted, false otherwise.
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[editar] Excepciones

noexcept specification:  
noexcept
  (desde C++11)

[editar] Notas

expired() puede ser más rápido que use_count() .
Original:
expired() may be faster than use_count().
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[editar] Ejemplo

Muestra cómo espirado se utiliza para comprobar la validez del puntero .
Original:
Demonstrates how expired is used to check validity of the pointer.
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#include <iostream>
#include <memory>
 
std::weak_ptr<int> gw;
 
void f()
{
    if (!gw.expired()) {
	std::cout << "gw is valid\n";
    }
    else {
        std::cout << "gw is expired\n";
    }
}
 
int main()
{
    {
        auto sp = std::make_shared<int>(42);
	gw = sp;
 
	f();
    }
 
    f();
}

Salida:

gw is valid
gw is expired


[editar] Ver también

crea una shared_ptr que gestiona el objeto referenciado
Original:
creates a shared_ptr that manages the referenced object
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(función miembro público) [editar]
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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(función miembro público) [editar]