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

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;

CodePudding user response：

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;
}