[avr-libc-dev] stdio input functions are now there

[Joerg Wunsch]

Hi,

in order to slowly complete our stdio implementation, i wrote the
basic input functions: fgetc(), fgets(), and all the derivatives
thereof.

The scanf family might be next, as time permits.  Like the printf
family, it will likely become huge and thus be implemented with
several options.

Also, all this lacks a good terminal driver example to be as useful
as one might expect it: if you just write the usual simple
uart_getchar() implementation like this, and provide it as the
put function to fdevopen():

int
uart_getchar(void)
{
  uint8_t c;

  loop_until_bit_is_set(UCSRA, RXC);
#ifdef UPE
  if (UCSRA & (_BV(FE) | _BV(DOR) | _BV(UPE)))
#else
  if (UCSRA & (_BV(FE) | _BV(DOR)))
#endif
    return -1;
  c = UDR;
  /* behaviour similar to Unix stty ICRNL */
  if (c == '\r')
    return (uint8_t)'\n';

  return c;
}

...it will basically do, but it will behave like a "raw" tty
stream under Unix, without any echo, without line-editing etc.
However, providing a more advanced example will be most useful
when it's also moved to an interrupt-drivne approach, but that's
beyond what my time currently permits.
-- 
J"org Wunsch                                           Unix support engineer
address@hidden        http://www.interface-systems.de/~j/