Implementing Callback Functions in C

# Introduction

In this project, you will learn how to implement a callback function in C language. Callback functions are a powerful technique in C programming, especially in the context of Linux system development, where they are commonly used.

## 👀 Preview

$ gcc test_callback.c callback.c -o test_callback
$ ./test_callback
Alarm1:0
Alarm2:1
Alarm3:2

## 🎯 Tasks

In this project, you will learn:

- How to define and use callback functions in C
- How to register and trigger alarms using a callback function
- How to handle edge cases and errors in the callback function implementation

## 🏆 Achievements

After completing this project, you will be able to:

- Understand the concept of callback functions and their usage in C programming
- Implement a callback-based alarm system, including registering and triggering alarms
- Write robust and defensive code to handle potential issues in the callback function
- Apply your knowledge of callback functions to other areas of C programming, such as event-driven systems or asynchronous operations