EOF character changing

[Guy Harris]

> System III and friends in raw mode have both a
> minimum-character threshold and a time threshold before waking up
> the reading process, the intent being a reduction of system load.
> Unfortunately, they decided to multiplex the character-count and
> time thresholds into already existing variables, namely the EOF and
> the BRK (I think) character.  So, the ioctl code automatically sets
> these fields to the 'appropriate' values when switching between raw
> and cooked mode (ICANON mode for those systems).

The TCSETA ioctl code doesn't do this (so be warned - if you just turn off
ICANON without fiddling VMIN/VEOF and VTIME/VEOL values, you may get a
surprise), but the TIOCSETP "backward compatibility" ioctl (which is *not*
backward compatible with V7, but with UNIX/TS 1.0, PWB/UNIX 2.0, etc.)
does do it when entering/leaving RAW mode.  The "stty" command also may
be doing it.

	Guy Harris
	{seismo,ihnp4,allegra}!rlgvax!guy