Do Built-in Types Support Move Semantics?

Rvalue Reference Semantics and Built-in Types

In the example code provided, a built-in type, namely an integer variable, is passed to the function Func as an r-value reference (&&). The output demonstrates that the integer's value is modified within the function.

The question arises: Do built-in types possess move semantics, and is the observed behavior well-defined?

Moving Built-in Types

Moving an object entails transferring ownership of resources from one object to another. Since built-in types are the resources themselves, transferring their resources is impractical. The example, however, shows that the variable's value is indeed modified, suggesting it's the resource being altered.

Understanding the Role of std::move

std::move plays a specific role: it converts an lvalue (variable) into an xvalue, allowing it to bind to r-value references. It doesn't trigger any constructors or runtime actions; the value category change occurs solely at the type level.

Behavior of Rvalue References

Rvalue references, despite their name, are still references that point to the original object. In this case, the function increments the original variable through the provided reference.

When a function accepts a parameter by reference (as opposed to value), no copies or moves occur; the original object is directly referenced.

Move Semantics and Fundamental Types

Fundamental types, like integers, lack move constructors. In these instances, moves degenerate into copies. The example demonstrates this behavior, as the integer's value is modified through a copy rather than a true move.

In summary, while built-in types do not have dedicated move semantics, the observed behavior of modifying the integer variable is valid because std::move allows r-value binding without invoking move constructors or moves.

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