Arena Allocation in C

Memory management is painful.

malloc is slow.
free is annoying.
Fragmentation is real.

So what if we never free individual allocations?

Welcome to arena allocators.

What is an Arena?

An arena (also called a region allocator) is a large chunk of memory where:

• You allocate sequentially.
• You never free individual allocations.
• You reset everything at once.

Think of it like a stack, but for general memory usage.

Why Use Arenas?

• Extremely fast allocations
• No fragmentation
• Simple mental model
• Perfect for temporary allocations

This Series Covers

1. Building a basic arena
2. Adding alignment support
3. Error handling and safety
4. Real-world usage patterns

Let’s build one from scratch.

Continue to Part 1.