std::shared_ptr::owner_before
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| template< class T > bool owner_before( const shared_ptr<T>& other) const; |
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| template< class T > bool owner_before( const std::weak_ptr<T>& other) const; |
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Prüft, ob diese
shared_ptr other vorangeht Umsetzung Inhaber-basiert (zur wertorientierten Gegensatz) definierten Reihenfolge. Die Reihenfolge ist, so dass zwei Smartpointer gleichwertig nur wenn beide leer ist oder wenn sie beide eigene dasselbe Objekt sind vergleichen, auch wenn sich die Werte der Zeiger durch get () erhaltenen unterschiedlichen (zB sind, weil sie auf verschiedenen Unterobjekte innerhalb derselben hinweisen Objekt)Original:
Checks whether this
shared_ptr precedes other in implementation defined owner-based (as opposed to value-based) order. The order is such that two smart pointers compare equivalent only if they are both empty or if they both own the same object, even if the values of the pointers obtained by get() are different (e.g. because they point at different subobjects within the same object)The text has been machine-translated via Google Translate.
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Diese Reihenfolge wird verwendet, um gemeinsam und schwache Hinweise einsetzbar als Schlüssel in assoziative Container, typischerweise durch std::owner_less .
Original:
This ordering is used to make shared and weak pointers usable as keys in associative containers, typically through std::owner_less.
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Inhaltsverzeichnis |
[Bearbeiten] Parameter
| other | - | die std::shared_ptr oder std::weak_ptr verglichen werden
Original: the std::shared_ptr or std::weak_ptr to be compared The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
[Bearbeiten] Rückgabewert
true wenn *this vorangeht
other, false anders. Gemeinsame Implementierungen vergleichen die Adressen der Steuerblöcke .Original:
true if *this precedes
other, false otherwise. Common implementations compare the addresses of the control blocks.The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
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[Bearbeiten] Beispiel
#include <iostream> #include <memory> struct Foo { int n1; int n2; Foo(int a, int b) : n1(a), n2(b) {} }; int main() { auto p1 = std::make_shared<Foo>(1, 2); std::shared_ptr<int> p2(p1, &p1->n1); std::shared_ptr<int> p3(p1, &p1->n2); std::cout << std::boolalpha << "p2 < p3 " << (p2 < p3) << '\n' << "p3 < p2 " << (p3 < p2) << '\n' << "p2.owner_before(p3) " << p2.owner_before(p3) << '\n' << "p3.owner_before(p2) " << p3.owner_before(p2) << '\n'; std::weak_ptr<int> w2(p2); std::weak_ptr<int> w3(p3); std::cout // << "w2 < w3 " << (w2 < w3) << '\n' // won't compile // << "w3 < w2 " << (w3 < w2) << '\n' // won't compile << "w2.owner_before(w3) " << w2.owner_before(w3) << '\n' << "w3.owner_before(w2) " << w3.owner_before(w2) << '\n'; }
Output:
p2 < p3 true p3 < p2 false p2.owner_before(p3) false p3.owner_before(p2) false w2.owner_before(w3) false w3.owner_before(w2) false
[Bearbeiten] Siehe auch
| (C++11) |
bietet eine Ordnung anhand der Eigentümer für gemischte Mengen aus shared_ptr und weak_ptr an (Klassen-Template) |
