# Introduction to the Heap

Unlike the stack, heap is an area of memory that can be dynamically allocated. This means that when you need new space, you can "request" more from the heap.

In C, this often means using functions such as `malloc()` to request the space. However, the heap is very slow and can take up tons of space. This means that the developer has to tell libc when the heap data is "finished with", and it does this via calls to `free()` which mark the area as available. But where there are humans there will be implementation flaws, and no amount of protection will ever ensure code is completely safe.

In the following sections, we will only discuss 64-bit systems (with the exception of some parts that were written long ago). The theory is the same, but pretty much any heap challenge (or real-world application) will be on 64-bit systems.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://ir0nstone.gitbook.io/notes/binexp/heap/introduction-to-the-heap.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.