Memory Safety Patterns

Cross-language patterns for memory-safe programming including RAII, ownership, smart pointers, and resource management.

When to Use This Skill

Writing memory-safe systems code
Managing resources (files, sockets, memory)
Preventing use-after-free and leaks
Implementing RAII patterns
Choosing between languages for safety
Debugging memory issues

Core Concepts

1. Memory Bug Categories

Bug Type	Description	Prevention
Use-after-free	Access freed memory	Ownership, RAII
Double-free	Free same memory twice	Smart pointers
Memory leak	Never free memory	RAII, GC
Buffer overflow	Write past buffer end	Bounds checking
Dangling pointer	Pointer to freed memory	Lifetime tracking
Data race	Concurrent unsynchronized access	Ownership, Sync

2. Safety Spectrum

Manual (C) → Smart Pointers (C++) → Ownership (Rust) → GC (Go, Java)
Less safe                                              More safe
More control                                           Less control

Detailed patterns and worked examples

Detailed pattern documentation lives in references/details.md. Read that file when the navigation tier above is insufficient.

Best Practices

Do's

Prefer RAII - Tie resource lifetime to scope
Use smart pointers - Avoid raw pointers in C++
Understand ownership - Know who owns what
Check bounds - Use safe access methods
Use tools - AddressSanitizer, Valgrind, Miri

Don'ts

Don't use raw pointers - Unless interfacing with C
Don't return local references - Dangling pointer
Don't ignore compiler warnings - They catch bugs
Don't use unsafe carelessly - In Rust, minimize it
Don't assume thread safety - Be explicit

Debugging Tools

# AddressSanitizer (Clang/GCC)
clang++ -fsanitize=address -g source.cpp

# Valgrind
valgrind --leak-check=full ./program

# Rust Miri (undefined behavior detector)
cargo +nightly miri run

# ThreadSanitizer
clang++ -fsanitize=thread -g source.cpp

memory-safety-patterns