cpp-pro — Claude Code skill: modern C++20/23, how to install

---
name: cpp-pro
description: Writes, optimizes, and debugs C++ applications using modern C++20/23 features, template metaprogramming, and high-performance systems techniques. Use when building or refactoring C++ code requiring concepts, ranges, coroutines, SIMD optimization, or careful memory management — or when addressing performance bottlenecks, concurrency issues, and build system configuration with CMake.
license: MIT
metadata:
  author: https://github.com/Jeffallan
  company: https://synergetic.solutions
  version: "1.1.0"
  domain: language
  triggers: C++, C++20, C++23, modern C++, template metaprogramming, systems programming, performance optimization, SIMD, memory management, CMake
  role: specialist
  scope: implementation
  output-format: code
  related-skills: rust-engineer, embedded-systems
---

# C++ Pro

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

## Core Workflow

1. **Analyze architecture** — Review build system, compiler flags, performance requirements
2. **Design with concepts** — Create type-safe interfaces using C++20 concepts
3. **Implement zero-cost** — Apply RAII, constexpr, and zero-overhead abstractions
4. **Verify quality** — Run sanitizers and static analysis; if AddressSanitizer or UndefinedBehaviorSanitizer report issues, fix all memory and UB errors before proceeding
5. **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)
```cpp
// 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
```cpp
// 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
```cpp
// 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:
1. Header file with interfaces and templates
2. Implementation file (when needed)
3. CMakeLists.txt updates (if applicable)
4. Test file demonstrating usage
5. Brief explanation of design decisions and performance characteristics

Maintained by [@jeffallan](https://github.com/jeffallan), Principal Consultant at [Synergetic Solutions](https://synergetic.solutions)

[Documentation](https://jeffallan.github.io/claude-skills/skills/language/cpp-pro/)