Examples of using Rvalue reference in English and their translations into Vietnamese
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Colloquial
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Ecclesiastic
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Computer
What is“rvalue reference for*this”?
C++11's answer to this problem is rvalue references.
Well, named rvalue references are lvalues;
Note that in both factory functions, the return type is a value,not an rvalue reference.
Rvalue references went through several versions.
The call of a function that returns an rvalue reference, such as std:: move, is an xvalue.
Rvalue references to functions are treated as lvalues whether named or not.
In that case,a temporary of type X is created, and the rvalue reference is bound to that temporary.
T&& is not an rvalue reference, but a forwarding reference. .
Example: The result of calling a function whose return type is an rvalue reference is an xvalue.- end example.
An rvalue reference X&& is a new kind of reference that only binds to rvalues.
Im: has identity andcan be moved from(e.g. the result of casting an lvalue to a rvalue reference).
Returning by rvalue reference gives me a prvalue, and returning by value gives me an xvalue.
You might expect T&& to only bind to rvalues, because at first glance,it looks like an rvalue reference.
But in the actual scope, a rvalue reference is a name to an object, so, it acts as a named object.
Only with both of lvalue and rvalue, the move semantics, perfect forward and rvalue reference still are work well.
C++1x will allow non-const rvalue references, spelled T&&, which are references to an rvalue objects.
As you can see, move accepts any kind of parameter thanks to the forwarding reference T&&,and it returns an rvalue reference.
They do, like intended, prefer rvalue references during overloading, and won't bind to non-const lvalue references. .
The result of calling a function, whether implicitly or explicitly,whose return type is an rvalue reference to the type of object being returned, or.
Rvalue references are still references, and as always, you should never return a reference to an automatic object;
Try to write a set of outer() functions which implement this without rvalue references, deducing the right way to pass the arguments from inner()'s type.
Since version 2.1, an rvalue reference X&& also binds to all value categories of a different type Y, provided there is an implicit conversion from Y to X.
Moving is exclusively performed by the move constructor, not by std:: move,and not by merely binding an rvalue to an rvalue reference.
C++0x introduces a new mechanism called"rvalue reference" which, among other things, allows us to detect rvalue arguments via function overloading.
And two groupings are done to capture those that can be qualified and can have different dynamic types(glvalues)and those where overloading prefers rvalue reference binding(rvalues).
If you look at its type, you see an rvalue reference, but an rvalue reference simply means"a reference that is bound to an rvalue";
Given a type TR that is a reference to a type T, an attempt to create the type“lvalue reference to cv TR” creates the type“lvalue reference to T”,while an attempt to create the type“rvalue reference to cv TR” creates the type TR.".
Note that returning by rvalue reference is fine in this example, because t does not denote an automatic object, but instead an object that was passed in by the caller.
With the introduction of them, it was said that an unnamed rvalue reference evaluates to an rvalue, such that overload resolution would prefer rvalue reference bindings, which would make it select move constructors over copy constructors.