c-cpp-dev

C/C++ Development

Language baseline is project-specific: check the project's CLAUDE.md, build system (-std= flags), or compiler configuration. All rules assume 32-bit ARM target unless otherwise noted.

Code Generation

• Respect the project's configured language standard. Don't assume a default.
• When a header is shared between C and C++ translation units, never define variables in the header — not even with static. Use extern in the header and exactly one definition in a single .c file.
• Allow goto when it simplifies cleanup or reduces complexity, but use it as a maintenance tool, not a first choice.
• Place Doxygen comments in header files. Keep implementation files focused on behavior.
• Avoid inline functions in header files. Keep function definitions in source files so the interface stays small.
• In C, lightweight macros or helper wrappers are acceptable if simple, local, and clearly named.

Memory Layout

• Watch local variable bursts inside functions. Large automatic arrays, structs, or many temporaries are stack budget items.
• Design structures with both semantics and byte alignment in mind. For protocol parsing, byte streams, and wire formats, make packing and endianness explicit.
• Use pragma or packing attributes only when they match a wire-format requirement and are documented clearly.
• Use double precision and 64-bit integers with caution on 32-bit targets. Operations on 64-bit objects create performance, compatibility, and atomicity problems unless the wider width is clearly required.
• When a 64-bit value crosses a task, interrupt, or module boundary, make its access pattern explicit: copied, split, guarded, or protected from tearing.