ft_get_next_line

Description

get_next_line is a function that reads a file line by line. It is a function that is part of the 42 curriculum and is used to teach students how to use static variables and memory allocation in C.

Installation

1. Clone the repository:

git clone https://github.com/abouabra/42-get_next_line.git

2. Change the current working directory:

cd 42-get_next_line

To use the get_next_line function in your project, include the get_next_line.h header file in your source code:

#include "get_next_line.h"

Usage

The get_next_line function reads a file descriptor and returns a line ending with a newline character from a file descriptor. The function returns the line that was read with the newline character. The function returns NULL when the reading is finished or an error occurs.

char* get_next_line(int fd);

Example

Mandatory

in order to read a file line by line, you can use the following code:

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

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

    fd = open("example.txt", O_RDONLY);
    if (fd == -1)
    {
        printf("Error: Could not open file\n");
        return (1);
    }
    while (true)
    {
        line = get_next_line(fd);
        if (line == NULL)
            break;
        printf("%s", line);
        free(line);
    }
    close(fd);
    return (0);
}

1. Compile your source code with the get_next_line.c file:

gcc -Wall -Wextra -Werror -D BUFFER_SIZE=32 example.c get_next_line.c -o example

2. Run the executable:

./example

3. The output will be the content of the file example.txt printed line by line.

Note

The BUFFER_SIZE macro is used to define the size of the buffer used to read the file. The BUFFER_SIZE must be greater than 0 and less than or equal to INT_MAX (limits.h). The BUFFER_SIZE can be defined at compile time using the -D flag or in the source code using the #define directive.

Bonus

The get_next_line function from the bonus version get_next_line_bonus.c can be used to read from multiple file descriptors. The function can be used to read from standard input, a file, or a network socket.

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

int main(void)
{
    int fd1;
    int fd2;
    char *line;

    fd1 = open("example1.txt", O_RDONLY);
    if (fd1 == -1)
    {
        printf("Error: Could not open file\n");
        return (1);
    }
    fd2 = open("example2.txt", O_RDONLY);
    if (fd2 == -1)
    {
        printf("Error: Could not open file\n");
        return (1);
    }
    while (true)
    {
        line = get_next_line(fd1);
        if (line == NULL)
            break;
        printf("%s", line);
        free(line);
        line = get_next_line(fd2);
        if (line == NULL)
            break;
        printf("%s", line);
        free(line);
    }
    close(fd1);
    close(fd2);
    return (0);
}

1. Compile your source code with the get_next_line_bonus.c file:

gcc -Wall -Wextra -Werror -D BUFFER_SIZE=32 example_bonus.c get_next_line_bonus.c -o example_bonus

2. Run the executable:

./example_bonus

3. The output will be the content of the files example1.txt and example2.txt printed line by line.

Final Note

If you have any suggestions or improvements, feel free to open an issue or submit a pull request.