Why Didn\'t Early C 11 Drafts Include Implicit Move Semantics?

Understanding the Lack of Default Move Semantics in Early C 11 Drafts

In the early stages of the C 11 standard, programmers questioned why compilers did not automatically generate default move constructors and assignment operators. This raised concerns for those seeking to leverage the move semantics of POD-types and STL containers without the need for explicit implementations.

Historical Reason for Implicit Move Semantics

The drive for implicit move semantics stemmed from the inherent safety of using std::move on immovable objects, which effectively utilized the assignment operator. However, this practice presented limitations in early C 11 drafts.

Implicit Move Semantics in the Current Standard

The latest C standard (N3225) has revised the conditions for implicit generation of move constructors and assignment operators. Currently, compilers will implicitly declare move constructors if:

• No user-defined copy constructor or copy assignment operator exists
• No user-defined move assignment operator is present
• No user-defined destructor exists
• The move constructor is not explicitly defined as deleted

Addressing the Lack of Move Semantics in Early Drafts

Initially, there was no clear workaround for the absence of implicit move semantics in early C 11 drafts. However, the latest standard changes provide the necessary conditions for automatic move generation.

Conclusion

The evolution of implicit move semantics in C 11 has addressed the concerns of developers seeking convenient and safe move operations. By understanding the historical reasons and current standard requirements, programmers can effectively utilize move semantics in their code.

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