bug#72778: 31.0.50; Calc: g f doesn't display gnuplot window after closing

[Michael Heerdegen via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Eli Zaretskii <eliz@gnu.org> writes:

> IME, gnuplot is notorious in changing its non-interactive behavior
> from time to time, which might break the assumptions that Calc makes.
> Suggest to look in the gnuplot's change log to see if they made some
> change in the recent years, maybe this will give some ideas.

I'm too ignorant to know what to look for.

Some more data points, though:

 - In *Gnuplot Trail* I see that gnuplot receives the command and emits
   a new prompt even when the command is ignored.

 - Executing (calc-gnuplot-command "set term wxt") (be sure that it is
   not ignored!) fixes the problem for me.  I guess we don't want to do
   that.

 - I can't reproduce the issue with a terminal emulator even when
   changing the gnuplot terminal to x11 (this is what Emacs uses for its
   gnuplot process).

I don't know much about process communication, excuse me if this is all
irrelevant.


Michael.