C++ Coding Standards

File: skills/cpp-coding-standards/SKILL.md Reference: C++ Core Guidelines

Essential Rules

Functions

• Cheap types by value, expensive by const&, sink parameters by value (for move)
• Return structs for multiple outputs, not output parameters
• Use constexpr and noexcept where applicable
• Prefer pure functions

Classes

• Rule of Zero: Let compiler generate special members when possible
• Rule of Five: If managing a resource, define all five (destructor, copy/move constructor, copy/move assignment)
• Single-argument constructors: explicit
• Base class destructors: public virtual or protected non-virtual
• Use override for virtual function implementations

Resource Management

• unique_ptr for exclusive ownership, shared_ptr for shared
• Raw pointer = non-owning observer
• No naked new/delete, no malloc/free

Expressions

• Always initialize objects at declaration
• Prefer {} initializer syntax
• Default to const/constexpr
• Use nullptr (not 0/NULL), no C-style casts, no magic numbers

Error Handling

• Custom exception types (not built-in types)
• Throw by value, catch by reference
• RAII for exception-safe code

Concurrency

• RAII locks (scoped_lock/lock_guard), always named
• scoped_lock for multiple mutexes (deadlock-free)
• Always wait with a condition on condition variables
• Don't use volatile for synchronization

Templates (C++20)

• Constrain with concepts (std::integral, custom concepts)
• Use using over typedef
• Avoid template metaprogramming where constexpr suffices

Style

• enum class over plain enum
• underscore_style naming, ALL_CAPS for macros only
• '\n' instead of std::endl
• Include guards, self-contained headers, no using namespace in headers

Quick Checklist

No raw new/delete | Objects initialized | const/constexpr by default | enum class | nullptr | No narrowing conversions | explicit constructors | Rule of Zero/Five | Concepts on templates | RAII locks | Custom exceptions | No magic numbers

Remember: Modern C++ emphasizes safety, clarity, and zero-overhead abstractions.