New warning about inline data and multiplots

[Dima K. <gn...@di...>]

Hello.

I just ran the gnuplotlib unit test, and I see lots of warnings with one
of the tests. The plots are still made, but there's A LOT of console
chatter now:

  "/tmp/tst.gp" line 17: warning: Reading from '-' inside a multiplot not supported; use a datablock instead
  "/tmp/tst.gp" line 18: warning: Reading from '-' inside a multiplot not supported; use a datablock instead
  "/tmp/tst.gp" line 19: warning: Reading from '-' inside a multiplot not supported; use a datablock instead
  "/tmp/tst.gp" line 20: warning: Reading from '-' inside a multiplot not supported; use a datablock instead
  "/tmp/tst.gp" line 21: warning: Reading from '-' inside a multiplot not supported; use a datablock instead

This keeps repeating many times. Cut-down python script:

  import numpy as np
  import gnuplotlib as gp

  xx,yy = np.meshgrid(np.linspace(-5,5,20),
                      np.linspace(-5,5,20))
  zz0 = np.sin(xx) + yy*yy/8.
  gp.plot3d( (zz0,
              dict(_set = ( 'origin 0,0',
                            'size 1,1',
                            'view 60,20,1,1',
                            'xrange [0:20]',
                            'yrange [0:20]',
                            'zrange [0:10]',
                            'contour base',
                            'xyplane at 10',))),
             tuplesize=3,
             _with = 'lines nosurface',
             square=1,
             wait=True,
             hardcopy='/tmp/tst.gp',
             ascii=True,
             multiplot=True)

The resulting gnuplot script is attached. It clearly shows the warnings.

What isn't supported here? I've been doing this for years with great
success, and it appears to still work today. Should I be doing something
different? I use gnuplot constantly, every day. But 99% of my usage is
either through feedgnuplot or gnuplotlib, both of which use inline data.
Should those tools be using a datablock? Can they?

Thanks.