The C++ standards committee abandoned a detailed proposal to create a rigorously safe subset of the language, according to the proposal’s co-author, despite continuing anxiety about memory safety.
“The Rust safety model is unpopular with the committee.Further work on my end won’t change that. Profiles won the argument.
“The Safety and Security working group voted to prioritize Profiles over Safe C++.Ask the Profiles people for an update. Safe C++ is not being continued,” said Sean Baxter in June this year.
The topic came up as developers like simone Bellavia noted the anniversary of the proposal.One year ago, Baxter told The Register that the project would enable C++ developers to get the memory safety of Rust, but without having to learn a new language.”Safe C++ prevents users from writing unsound code,” he said. “This includes compile-time intelligence like borrow checking to prevent use-after-free bugs and initialization analysis for type safety.”
Safe C++ would enable incremental migration of code, as it only applies to code in the safe context. Existing unsafe code would run as before.
Even the matter of whether the proposal has been abandoned is not clear-cut. Erich Keane, C++ committee member and co-chair of the C++ Evolution Working Group (EWG), said that Baxter’s proposal “got a vote of encouragement where roughly 1/2 (20/45) of the people encouraged Sean’s paper, and 30/45 encouraged work on profiles (with 6 neutral)… Sean is completely welcome to continue the effort, and many in the committee would love to see him make further effort on standardizing it.”
In response, Baxter said: “The Rust safety model is unpopular with the committee. Further work on my end won’t change that. Profiles won the argument.”
How do C++ Language Profiles address security concerns differently than the proposed Safe C++ initiative?
Table of Contents
- 1. How do C++ Language Profiles address security concerns differently than the proposed Safe C++ initiative?
- 2. C++ Safe Proposal Sidelined for Language Profiles Growth
- 3. The Shift in C++ Standardization: A Focus on Profiles
- 4. What are C++ Language profiles?
- 5. Why the Shift Away from safe C++?
- 6. Implications for C++ Security and Development
- 7. The Role of Modern C++ Features in Security
- 8. Current Status and Future Outlook
C++ Safe Proposal Sidelined for Language Profiles Growth
The Shift in C++ Standardization: A Focus on Profiles
recent developments within the C++ standards committee have seen a significant shift in priorities. The “Safe C++” proposal, aiming to introduce a formally verified subset of C++ designed to eliminate entire classes of vulnerabilities, has been largely sidelined in favor of developing Language Profiles. This change has sparked debate within the C++ community, raising questions about the future direction of the language and its commitment to security. Understanding this shift requires delving into the motivations behind Language Profiles and the implications for the Safe C++ initiative.
What are C++ Language profiles?
Language Profiles represent a pragmatic approach to managing the complexity of C++. Instead of attempting to define a single, universally safe subset, profiles define constrained subsets of the language tailored for specific use cases. Think of them as pre-configured C++ environments optimized for particular domains.
Here’s a breakdown of key aspects:
* Targeted Applications: Profiles are designed for areas like embedded systems, automotive software, high-integrity systems, and safety-critical applications.
* Subset Definition: Each profile specifies which language features are permitted and which are prohibited. This restriction aims to simplify verification and reduce the potential for errors.
* Conformance Checking: Tools will be developed to verify that code conforms to a specific profile, ensuring it adheres to the defined constraints.
* Coexistence with Full C++: Profiles don’t replace the full C++ standard. Developers can still use the complete language when appropriate, but profiles offer a safer option for specific projects.
Why the Shift Away from safe C++?
The Safe C++ proposal,while ambitious and theoretically sound,faced several hurdles:
* Complexity: Implementing a formally verified subset of C++ is an incredibly complex undertaking.The language’s history and inherent adaptability made it tough to define a truly safe core without severely limiting expressiveness.
* Performance Concerns: The restrictions imposed by Safe C++ risked introducing significant performance overhead, making it unsuitable for manny applications.
* Tooling Challenges: Developing compilers and static analysis tools capable of enforcing the Safe C++ rules proved to be a substantial challenge.
* Adoption Rate: Concerns existed about the potential for low adoption rates if the resulting language subset was too restrictive or difficult to use.
The standards committee ultimately concluded that Language Profiles offered a more practical and achievable path towards improving C++ security and reliability. Profiles allow for a more incremental approach,focusing on specific domains where safety is paramount.
Implications for C++ Security and Development
The prioritization of Language Profiles has significant implications for C++ developers:
* Increased Focus on Static Analysis: Conformance checking tools will become crucial for ensuring code adheres to profile constraints. Expect increased investment in static analysis and formal verification technologies.
* Domain-Specific Development: Developers working in safety-critical domains will likely adopt profiles tailored to thier specific needs. This will lead to more specialized C++ development workflows.
* Potential for Fragmentation: The proliferation of profiles could lead to fragmentation within the C++ ecosystem, with different subsets of the language being used in different contexts. Standardization efforts will be vital to mitigate this risk.
* Continued Relevance of Secure Coding Practices: Even with profiles,secure coding practices remain essential. Profiles reduce the potential for vulnerabilities,but they don’t eliminate them entirely. Understanding concepts like memory safety, data validation, and exception handling is still critical. Consider techniques like RAII (Resource Acquisition Is Initialization) and the use of smart pointers to manage resources effectively. As highlighted in recent discussions, C++11’s right values and move semantics are crucial for performance, especially when dealing with dynamic resources.
The Role of Modern C++ Features in Security
While the Safe C++ proposal is on hold, modern C++ features continue to contribute to improved security:
* Smart Pointers ( std::unique_ptr, std::shared_ptr): Automate memory management, reducing the risk of memory leaks and dangling pointers.
* constexpr: Enables compile-time evaluation of expressions, perhaps catching errors earlier in the development process.
* Strong Typing: C++’s strong typing system helps prevent many common programming errors.
* Range-Based For Loops: Reduce the risk of off-by-one errors when iterating over containers.
* Exception Handling: Provides a structured way to handle errors and prevent program crashes.
Current Status and Future Outlook
As of September 2025, the C++ standards committee is actively working on defining the first set of Language Profiles. The initial focus is on profiles for embedded systems and automotive
