[Gnuplot-info] gnuplot as subprocess

[shishir <sh...@ct...>]

hi,
I'm generating some data that is fed to gnuplot like this:
--
plot '-' u 1:2 w l
1 2
3 4
5 6
end
pause 20
--
and I use it like this:
main_prog | gnuplot     (here main_prog generates six lines as above.)

is it posible to make the appearing plot interactive, i.e. I can zoom
in-out of it?
(gnuplot -persist will not work)

I may do it via writing some code in C-gnuplot interface, there should
be some easier solution.
Is there some stream identifier which says to gnuplot that what command
have given to you work on them and wait for more.  (in my problem gnuplot
waits to read all the stream and work on that in the end).

thanks.
ps: the discussion on same topic sometime earlier doesn't provide a solution
for this.