018-hirst-painting/.claude/skills/coding-conventions/references/cpp.md

C++ conventions

Standard base

ISO C++17 or later as set by the project (-std=c++20); the C++ Core Guidelines are the rule source. C++ has no official naming style, so the style below is used unless the project already has another (rule 1 of the overall skill).

Naming

Element	Convention	Example
Class, struct, enum, concept, type alias	PascalCase	StayReader, Stay
Function, method, variable, parameter	snake_case	read_stays(), byte_count
Data member (private)	snake_case with trailing underscore	buffer_
Struct public data member	snake_case, no underscore	check_in
Constant (constexpr, namespace-scope const)	kPascalCase	kMaxRetries
Enum class value	PascalCase	Status::NotFound
Namespace	short snake_case; no using namespace in headers	billing
Template parameter	PascalCase	typename ItemT
Macro	UPPER_SNAKE with project prefix; avoid macros	BILLING_ASSERT
Header / source file	snake_case.h / snake_case.cpp, same base name	stay_reader.h
Header guard	#pragma once (or PROJECT_PATH_FILE_H)

Formatting

• clang-format with one checked-in config; 4 spaces (or the project's setting); braces on every control-flow body.
• Include order: matching header, project headers, third party, standard library; each group sorted.
• One declaration per line; declare at first use, initialise with {}.

Language rules

• Ownership: RAII everywhere. No owning raw pointers, no naked new/delete; use std::unique_ptr by default, std::shared_ptr only for real shared ownership, created with std::make_unique/make_shared.
• Follow the rule of zero; if you define one of destructor, copy or move, define or delete all five.
• Pass by const& (large, read-only) or by value (small or sink); use std::span and std::string_view for non-owning views, std::optional for "maybe", std::variant for alternatives.
• const and constexpr by default; mark single-argument constructors explicit; mark override/final; [[nodiscard]] on results that must be used.
• Prefer algorithms and range-for over hand-written loops; enum class over plain enum; nullptr over NULL or 0; using over typedef.
• No C-style casts; use static_cast and friends. No mutable global state.
• Headers are self-contained and contain declarations, templates and inline definitions only.

Errors

Use exceptions for exceptional failures, or std::expected and error codes where the project forbids exceptions; one choice per project. Destructors never throw. Catch by const&; never catch (...) without rethrowing or logging.

Tests

GoogleTest, Catch2 or doctest; run under sanitizers (address, undefined) in at least one build.

Tooling

clang-format, clang-tidy with the Core Guidelines checks, compiler warnings (-Wall -Wextra -Wpedantic), sanitizers.

Review with QC-CPP-001.