name: cpp
description: Guidelines for modern C++ development with C++17/20 standards, memory safety, and performance optimization

C++ Development Guidelines

You are an expert in modern C++ development with deep knowledge of C++17/20 standards, memory management, and high-performance programming.

Code Style and Structure

• Write clean, modern C++ code following C++17/20 standards
• Use meaningful variable and function names
• Follow the Single Responsibility Principle
• Prefer composition over inheritance
• Keep functions small and focused

Naming Conventions

• Use PascalCase for classes and structs
• Use camelCase for functions, variables, and methods
• Use SCREAMING_SNAKE_CASE for constants and macros
• Use snake_case for namespaces
• Prefix member variables with m_ or use trailing underscore

Memory Management

Smart Pointers

• Use std::unique_ptr for exclusive ownership
• Use std::shared_ptr only when shared ownership is required
• Use std::weak_ptr to break circular references
• Avoid raw owning pointers

RAII (Resource Acquisition Is Initialization)

• Use RAII for all resource management
• Wrap resources in classes with proper destructors
• Ensure exception safety through RAII
• Use scope guards for cleanup operations

Best Practices

• Prefer stack allocation over heap allocation
• Use std::make_unique and std::make_shared
• Avoid new and delete in application code
• Use containers instead of raw arrays

Modern C++ Features

C++17 Features

• Use structured bindings for tuple unpacking
• Use std::optional for values that may not exist
• Use std::variant for type-safe unions
• Use if constexpr for compile-time conditionals
• Use std::string_view for non-owning string references

C++20 Features

• Use concepts for template constraints
• Use ranges for cleaner algorithms
• Use std::span for non-owning array views
• Use coroutines for asynchronous operations
• Use modules for faster compilation (when supported)

Error Handling

• Use exceptions for error handling
• Define custom exception types for domain-specific errors
• Use noexcept for functions that don't throw
• Catch exceptions by const reference
• Provide strong exception guarantees where possible

Performance

• Use const and constexpr liberally
• Prefer move semantics with std::move
• Use perfect forwarding with std::forward
• Avoid unnecessary copies
• Profile before optimizing
• Use inline for small frequently-called functions

Security

Buffer Safety

• Use std::array instead of C-style arrays
• Use std::vector with bounds checking
• Prefer std::string over C-style strings
• Use std::span for array views

Type Safety

• Avoid C-style casts; use static_cast, dynamic_cast, etc.
• Use enum class instead of plain enums
• Use nullptr instead of NULL
• Enable compiler warnings and treat them as errors

Concurrency

• Use std::thread and std::jthread for threading
• Use std::mutex and std::lock_guard for synchronization
• Use std::atomic for lock-free operations
• Prefer std::async for simple async operations
• Use condition variables for thread coordination

Testing

• Write unit tests with Google Test or Catch2
• Use mocking frameworks like Google Mock
• Test edge cases and error conditions
• Use sanitizers (ASan, UBSan, TSan) during testing
• Implement continuous integration testing

Documentation

• Use Doxygen-style comments for documentation
• Document public APIs thoroughly
• Include usage examples in documentation
• Keep documentation up to date with code changes
• Document thread safety requirements

Build System

• Use CMake for cross-platform builds
• Organize code into logical modules
• Use package managers (vcpkg, Conan) for dependencies
• Enable compiler warnings and static analysis
• Configure proper debug and release builds