Get Next Line

Overview

Get Next Line is a project focused on creating a function that reads and returns one line at a time from a file descriptor, whether from a file or standard input. The function continues to return each line every time it’s called, allowing for incremental reading. This project was a great exercise in handling memory, file descriptors, and buffer management efficiently.

I learned to work with static variables in C to maintain state across function calls without relying on global variables.

Key Features

• A get_next_line() function that reads and returns a line from a file descriptor.
• The function includes the newline character (\n) in the returned string if present.
• When there’s no more to read or in case of an error, the function returns NULL.
• Efficient memory usage by reading incrementally, avoiding the need to store the entire file in memory.

Example

Here’s how get_next_line() can be used in a loop to read a file line by line:

int fd;
char *line;

fd = open("file.txt", O_RDONLY);
line = get_next_line(fd);
while (line != NULL)
{
    printf("%s", line);
    free(line);
    line = get_next_line(fd);
}
close(fd);

Bonus Features

I also added the following bonuses:

• Manage multiple file descriptors simultaneously, allowing the function to handle multiple files without losing the reading thread for each.
• The function uses only one static variable.

Installation

1. Clone my repository:
2. Navigate to the project directory:

   cd Get Next Line

3. Compile the project using the provided Makefile:

   make

Requirements

• C programming language.
• Must use the read, malloc, and free functions. No global variables or the lseek() function allowed.

External Functions

The project uses the following external functions:

• read, malloc, free, and custom helper functions.