How to partially read input until a new line using read()?

I’m trying to partially read input until a new line is inputed "\n". But how can I do that with the read() function? Right now I’ve made the partial read until the terminal interface is logged out and the input is stopped (pressing ctrl+d on linux terminal), but don’t know how to make it stop when a new line is inputted. Here is my code:

int fd = 0;
const size_t read_size = 100;
size_t size = read_size;
char *buff = malloc(size+1);
size_t offset = 0;
size_t res = 0;

while((res = read(fd, buff + offset, read_size)) > 0)
{
    offset += res;
    buff[offset] = '\0';
    if (offset + read_size > size)
    {
        size *= 2;
        buff = realloc(buff, size+1);
    }
}
return buff;

>Solution :

I’m trying to partially read input until a new line is inputed "\n". But how can I do that with the read() function?

The only way you can achieve this with a read is to read one character at a time. Once you’ve read the '\n' character, stop.

how do I check what is being read?

while (read(fd, buf + offset, 1) == 1) {
  if (buf[offset] == '\n') break;
  offset += 1;
}