`std::make_unique` vs. `std::unique_ptr` with `new`: Is There a Performance Difference?

std::make_unique vs. std::unique_ptr with new: Exploring Efficiency and Usage

One of the key features introduced in modern C is the ability to manage memory allocation and ownership more efficiently using the std::unique_ptr smart pointer. However, the question arises: Does std::make_unique offer any performance benefits over the traditional approach of constructing a std::unique_ptr directly with the new operator?

Key Motivations for std::make_unique

Contrary to popular perception, the primary motivations behind std::make_unique are not related to runtime efficiency. Instead, std::make_unique excels in the following areas:

• Temporary Object Safety: Unlike raw pointers obtained through new, std::make_unique allows for the creation and use of temporary objects without the risk of dangling pointers.
• Simplified Syntax: std::make_unique eliminates the need for冗余类型声明, making code more concise and readable.

Comparison with Manual Construction

While std::make_unique offers advantages in terms of safety and syntax, it does not provide any significant efficiency benefits beyond the standard std::unique_ptr construction.

std::make_unique(1); vs. std::unique_ptr(new int(1));

Both of these expressions allocate memory for an integer and create a std::unique_ptr pointing to that memory. In terms of runtime efficiency, there is no discernible difference between these two approaches.

Conclusion

std::make_unique is primarily intended to improve the safety and usability of std::unique_ptr, rather than enhance its runtime performance. It is an invaluable tool for creating and managing objects with ownership semantics both efficiently and safely.

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