##### isatty

Synopsis:

                int isatty(int fd);

Request:
  ‘`Fisatty,fd`’
Return value:
  Returns 1 if fd refers to the gdb console, 0 otherwise.
Errors:
  `EINTR`
    The call was interrupted by the user.

Note that the `isatty` call is treated as a special case: it returns 1 to the target if the file descriptor is attached to the gdb console, 0 otherwise. Implementing through system calls would require implementing `ioctl` and would be more complex than needed.