get_next_line

---

Introduction

This project is a key part of the 42 school curriculum. The goal of get_next_line is to write a function that reads a line from a file descriptor, ending with a newline character (\n) or the end of the file.

This task is designed to teach you about static variables, file descriptors, and efficient memory management. The function must be able to read from multiple file descriptors at the same time without losing any data.

---

How It Works

The core challenge of get_next_line is to handle the partial reads from a file. Since a single read() call might return more than one line, or a partial line, the function needs a way to remember the leftover characters for the next call. This is where a static variable comes in.

• The static variable acts as a persistent buffer for each file descriptor.
• When get_next_line is called, it first checks this buffer for a complete line.
• If no line is found, it uses read() to fetch more data and appends it to the buffer.
• Once a newline character (\n) is encountered, the function extracts the line, updates the static buffer with the remaining characters, and returns the line.

---

Installation and Usage

To use the get_next_line function, simply compile the source files along with your main program.

Mandatory Files

• get_next_line.c
• get_next_line_utils.c (or combined into one file)
• get_next_line.h

Compilation

You can compile your program using the following command. The -D BUFFER_SIZE=42 part is optional but useful for testing different buffer sizes. The buffer size should be defined in the header file.

gcc -Wall -Wextra -Werror -D BUFFER_SIZE=42 main.c get_next_line.c get_next_line_utils.c -o gnl_test

Example

Here's a simple example of a main.c file that uses get_next_line to read from standard input:

#include "get_next_line.h"
#include <stdio.h>
#include <fcntl.h>

int main(void)
{
    char *line;
    int fd;

    // Reading from standard input
    printf("Enter text. Press Ctrl+D to stop.\n");
    fd = 0;
    while ((line = get_next_line(fd)))
    {
        printf("Read line: %s", line);
        free(line);
    }
    printf("Read line: %s", line);
    return (0);
}

---

Project Contributor

• Ruben Finnerud - rubenfin

---