std::shared_ptr::owner_before
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<metanoindex/>
<tbody> </tbody> 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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Verifica se esta
shared_ptr precede other na aplicação definida proprietário baseado (em oposição ao valor) ordem. A ordem é tal que dois ponteiros inteligentes comparar equivalente só se forem ambos vazios ou se ambos do próprio objeto, mesmo se os valores dos indicadores obtidos pelo get () são diferentes (por exemplo, porque eles apontam subobjetos diferentes dentro do mesmo objeto)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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Esta ordenação é usado para fazer partilhada e ponteiros fracos utilizável como chaves em recipientes associativos, tipicamente através 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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Parâmetros
| other | - | o std::shared_ptr ou std::weak_ptr a ser comparada
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. |
Valor de retorno
true se *this precede other, false contrário. Implementações comuns comparar os endereços dos blocos de controle.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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Exemplo
#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';
}
Saída:
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
Veja também
(C++11) |
fornece de tipo misto ordenação proprietário baseado de ponteiros compartilhados e fraco Original: provides mixed-type owner-based ordering of shared and weak pointers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (modelo de classe) |