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