readline rl_callback problems

[Adam Luter]

The attached program does not work.  If the select call ever times out,
you cannot type any more info.  I'm certain it's something wrong with
me; but I can't find any hint in the docs as to what I'm doing wrong.

Also, the commented out section is not necessary to generate the
problem, but I was wondering if it was also an acceptable approach.  The
idea is to clear the line, display the stuff you want to, then tell
readline to clean itself up.  Is there a better way to do this (i.e.
have output display while the user is typing a command)?

Lastly, if you do manage to exit the program (via ctrl-d) before the
timeout, you get two copies of the prompt.  Is there a way to avoid
this?

Thanks verily,
  Adam Luter