std::weak_ptr

 

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std::weak_ptr

Member-Funktionen 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=

Modifiers 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

Beobachter 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-Member-Funktionen 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

 

Defined in header <memory>
template< class T > class weak_ptr;		(seit C++11)

std::weak_ptr ist ein Smart-Pointer, die eine nicht-besitzenden ("schwache") Verweis auf ein Objekt, das durch std::shared_ptr verwaltet hält. Er muss std::shared_ptr umgewandelt werden, um den Zugriff auf das referenzierte Objekt .

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 Modelle temporären Eigentümer:. wenn ein Objekt, auf das zugegriffen nur wenn es vorhanden sein muss, und es kann jederzeit von einer anderen gelöscht werden, std::weak_ptr wird verwendet, um das Objekt zu verfolgen, und sie ist an std::shared_ptr umgewandelt vorübergehende Besitz übernehmen. Wenn die ursprüngliche std::shared_ptr zu dieser Zeit zerstört wird, das Objekt Lebensdauer verlängert wird, bis die temporäre std::shared_ptr als auch .

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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Zusätzlich std::weak_ptr dient Zirkelverweise von std::shared_ptr brechen .

Original:

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

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Mitglied Typen

Mitglied Typ 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

Member-Funktionen

(constructor)	schafft eine neue 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. (öffentliche Elementfunktion)
(destructor)	zerstört eine 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. (öffentliche Elementfunktion)
operator=	ordnet die 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. (öffentliche Elementfunktion)
Modifiers 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	löst das Eigentum des verwalteten Objekts 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. (öffentliche Elementfunktion)
swap	Swaps die verwalteten Objekte 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. (öffentliche Elementfunktion)
Beobachter 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	gibt die Anzahl der shared_ptr Objekte, die das Objekt verwalten 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. (öffentliche Elementfunktion)
expired	prüft, ob das referenzierte Objekt wurde bereits gelöscht 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. (öffentliche Elementfunktion)
lock	schafft eine shared_ptr, die das referenzierte Objekt verwaltet 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. (öffentliche Elementfunktion)
owner_before	bietet Inhaber-basierte Sortierung der schwachen Zeiger 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. (öffentliche Elementfunktion)

Non-Member-Funktionen

std::swap(std::weak_ptr) (C++11)	spezialisiert die std::swap Algorithmus 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. (Funktions-Template)

Beispiel

Veranschaulicht Wie Sperre verwendet wird, um die Gültigkeit des Zeigers zu gewährleisten .

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