std ::引用对 [英] std::pair of references

问题描述

是否有一个 std :: pair 引用的有效性？特别是，有赋值运算符的问题吗？根据此链接，似乎没有使用operator =进行特殊处理，因此默认分配操作符

Is it valid to have a std::pair of references ? In particular, are there issues with the assignment operator ? According to this link, there seems to be no special treatment with operator=, so default assignement operator will not be able to be generated.

我想要一个对< T&&>

I'd like to have a pair<T&, U&> and be able to assign to it another pair (of values or references) and have the pointed-to objects modified.

推荐答案

请注意，我说可靠。一些常见的编译器仍在使用（对于GCC，我测试了GCC4.1， @Charles 报告GCC4.4.4）做不允许形成对引用的引用，但最近 允许它实现引用折叠（ T& 是 T if T 是引用类型）。如果你的代码使用这样的东西，你不能依赖它来工作在其他编译器，直到你尝试看看。

Notice that I said "reliably". Some common compilers still in use (for GCC, I tested GCC4.1, @Charles reported GCC4.4.4) do not allow forming a reference to a reference, but more recently do allow it as they implement reference collapsing (T& is T if T is a reference type). If your code uses such things, you cannot rely on it to work on other compilers until you try it and see.

听起来你想使用 boost :: tuple<>

int a, b;

// on the fly
boost::tie(a, b) = std::make_pair(1, 2);

// as variable
boost::tuple<int&, int&> t = boost::tie(a, b);
t.get<0>() = 1;
t.get<1>() = 2;

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