Why Not Always Use Move Semantics

While move semantics can be more efficient than copy semantics, they are not always appropriate. Here are a few reasons why:

Reason 1: Move semantics modify the source object, leaving it in a valid but unspecified state. If you still need to use the source object after the move, it may not be in the expected state.

1Resource A;
2Resource B{std::move(A)};
3
4// Undefined behavior, A is in a moved-from state
5A.SomeFunction();

Reason 2: Not all types support move semantics. Built-in types like int and double don't have move constructors or move assignment operators. Attempting to use std::move() on them will just trigger a copy.

Reason 3: Move semantics are not always faster than copy semantics. For small objects or objects with cheap copy operations, the overhead of moving may be greater than copying.

Reason 4: Readability and maintainability are important. Overusing std::move() can make the code harder to understand and maintain, especially if it's not clear that the source object is no longer needed.

In general, use move semantics judiciously when you know the source object is no longer needed and when the type supports efficient moves. But don't feel compelled to use them everywhere just for the sake of optimization.