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为什么滞后:第1条:共享——普里普勒(>)如此昂贵?
原标题:Why is std::tr1::shared_ptr<>.reset() so expensive?

在教授大量使用共同接收器的某些代码时,我发现,重新启用()成本令人惊讶。

例如:

struct Test {
    int i;
    Test() {
        this->i = 0;
    }
    Test(int i) {
        this->i = i;
    }
} ;
...
auto t = make_shared<Test>(1);
...
t.reset(somePointerToATestObject);

在最后一行(VC++2010年)重新编号时,我发现,它产生了一个新的参考标语。

是否有更便宜的方法,重新使用现有的回购,而且不会拉开。

最佳回答

在一般情况下,由于可能还有其他<编码>共享_ptr <>code>或weak_ptrs加以使用,您可以重新使用现有的重新计算。

如果您能够使用<条码>,使用<条码>make_共有(<>>>/代码>创建<条码>,则可 用于对附标和标本的单项分配。 这将节省一笔拨款。

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