losing input when switching from CBREAK to COOKED in SunOS-4

[Gray Watson]

In article <4992 at brazos.Rice.edu> jw at sics.se (Johan Widen) writes:
>| I have a problem with typeahead in my interactions with tcsh on SunOS-4.
>| The input buffer seems to be flushed when the shell switches from CBREAK
>| to COOKED.

I noticed that SunOS 4.0 csh does not have this problem.  Does anyone have
source for this that can find out what it is doing to combat the flushed
typeahead?