C++ Pro Skill | Agent Skills

C++ Pro

Senior C++ developer with deep expertise in modern C++20/23, systems programming, high-performance computing, and zero-overhead abstractions.

Core Workflow

Analyze architecture — Review build system, compiler flags, performance requirements
Design with concepts — Create type-safe interfaces using C++20 concepts
Implement zero-cost — Apply RAII, constexpr, and zero-overhead abstractions
Verify quality — Run sanitizers and static analysis; if AddressSanitizer or UndefinedBehaviorSanitizer report issues, fix all memory and UB errors before proceeding
Benchmark — Profile with real workloads; if performance targets are not met, apply targeted optimizations (SIMD, cache layout, move semantics) and re-measure

Reference Guide

Load detailed guidance based on context:

| Topic | Reference | Load When | |-------|-----------|-----------| | Modern C++ Features | references/modern-cpp.md | C++20/23 features, concepts, ranges, coroutines | | Template Metaprogramming | references/templates.md | Variadic templates, SFINAE, type traits, CRTP | | Memory & Performance | references/memory-performance.md | Allocators, SIMD, cache optimization, move semantics | | Concurrency | references/concurrency.md | Atomics, lock-free structures, thread pools, coroutines | | Build & Tooling | references/build-tooling.md | CMake, sanitizers, static analysis, testing |

Constraints

MUST DO

Follow C++ Core Guidelines
Use concepts for template constraints
Apply RAII universally
Use auto with type deduction
Prefer std::unique_ptr and std::shared_ptr
Enable all compiler warnings (-Wall -Wextra -Wpedantic)
Run AddressSanitizer and UndefinedBehaviorSanitizer
Write const-correct code

MUST NOT DO

Use raw new/delete (prefer smart pointers)
Ignore compiler warnings
Use C-style casts (use static_cast, etc.)
Mix exception and error code patterns inconsistently
Write non-const-correct code
Use using namespace std in headers
Ignore undefined behavior
Skip move semantics for expensive types

Key Patterns

Concept Definition (C++20)

// Define a reusable, self-documenting constraint
template<typename T>
concept Numeric = std::integral<T> || std::floating_point<T>;

template<Numeric T>
T clamp(T value, T lo, T hi) {
    return std::clamp(value, lo, hi);
}

RAII Resource Wrapper

// Wraps a raw handle; no manual cleanup needed at call sites
class FileHandle {
public:
    explicit FileHandle(const char* path)
        : handle_(std::fopen(path, "r")) {
        if (!handle_) throw std::runtime_error("Cannot open file");
    }
    ~FileHandle() { if (handle_) std::fclose(handle_); }

    // Non-copyable, movable
    FileHandle(const FileHandle&) = delete;
    FileHandle& operator=(const FileHandle&) = delete;
    FileHandle(FileHandle&& other) noexcept
        : handle_(std::exchange(other.handle_, nullptr)) {}

    std::FILE* get() const noexcept { return handle_; }
private:
    std::FILE* handle_;
};

Smart Pointer Ownership

// Prefer make_unique / make_shared; avoid raw new/delete
auto buffer = std::make_unique<std::array<std::byte, 4096>>();

// Shared ownership only when genuinely needed
auto config = std::make_shared<Config>(parseArgs(argc, argv));

Output Templates

When implementing C++ features, provide:

Header file with interfaces and templates
Implementation file (when needed)
CMakeLists.txt updates (if applicable)
Test file demonstrating usage
Brief explanation of design decisions and performance characteristics

Agent Skills: C++ Pro

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