Get Next Line is a project at 42. It is a function that reads a file and allows you to read a line ending with a newline character from a file descriptor. When you call the function again on the same file, it grabs the next line
To use the function on your code, just include the header
#include "Path/get_next_line.h"
then compile your source code with this flag
gcc -D BUFFER_SIZE={size}