cpp-core-guidelines

C++ Core Guidelines by Stroustrup and Sutter for writing modern, safe, and efficient C++ code. Use when writing, reviewing, or refactoring C++ code to ensure type safety, resource safety, and performance. Triggers on C++ code tasks including interface design, resource management (memory, handles, locks), class design, error handling, concurrency, templates, and general code review. Use for questions like "review this C++ code", "how should I manage resources in C++", "best practices for C++ interfaces", or when writing any C++ code that should follow modern standards (C++11/14/17/20).

C++ Core Guidelines

Overview

These guidelines help write C++ code that is:

Type-safe: No implicit violations of the type system
Resource-safe: No leaks (memory, handles, locks, etc.)
Performant: Efficient without sacrificing correctness
Correct: Catches more logic errors at compile time

Load Reference by Scenario

Choose the reference file based on what you're doing:

| Scenario | Reference File | Rules | |----------|----------------|-------| | Checking memory leaks, RAII, pointers | memory-safety.md | R., ES., Con.* | | Designing function signatures, APIs | api-design.md | I., F. | | Designing or reviewing classes | class-design.md | C.* | | Thread safety, data races, locks | concurrency.md | CP.* | | Exceptions, error codes, error handling | error-handling.md | E.* | | Templates, STL, generic code | templates.md | T., SL., Enum.* | | Coding style, naming, philosophy | modern-style.md | P., NL., SF.* | | Performance optimization, C compatibility | performance.md | Per., CPL., A.* |

Quick Reference

Memory Safety

// Bad: manual management
X* p = new X;
delete p;

// Good: RAII
auto p = make_unique<X>();

API Design

// Bad: unclear ownership
void process(int* data, int n);

// Good: explicit ownership and size
void process(span<const int> data);

Class Design

// Rule of zero - let compiler generate
class Widget {
    unique_ptr<Impl> pImpl;  // No explicit dtor/copy/move needed
};

Concurrency

// Bad: manual lock
mutex mtx;
mtx.lock();
// ...
mtx.unlock();

// Good: RAII lock
lock_guard<mutex> lock(mtx);

Code Review Checklist

When reviewing C++ code, load the appropriate reference and check:

Memory Safety → memory-safety.md

[ ] No raw new/delete
[ ] RAII for all resources
[ ] No dangling pointers
[ ] Proper const usage

API Design → api-design.md

[ ] Interfaces are explicit
[ ] Parameters express ownership
[ ] Return values over output params

Class Design → class-design.md

[ ] Class has clear invariant
[ ] Rule of zero/five followed
[ ] Virtual destructor for base classes

Thread Safety → concurrency.md

[ ] No data races
[ ] lock_guard/scoped_lock used
[ ] No deadlocks