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