[Gnuplot-info] How to ignore "popen failed"?

[theozh <th...@gm...>]

Hi,
I would like to plot many files (under Windows) in a multiplot
environment using a loop.
The filenames without extensions are e.g.,
Data1a, Data1b, Data2, Data3, Data3a, Data3b, Data5a, ...

set multiplot layout 3,3
do for [i = 1:9] {
  FileList = system("dir /B /S Data".i."*.dat")
  plot for [FileName in FileList] FileName u 1:2 w l
}
unset multiplot

I want all Data1 in one plot, all Data2 in the next plot, etc.
It varies how many plots (a,b,c,...) of each.
However, it could also happen that, e.g. there is no "Data4" file.

In case there is no matching file in the directory gnuplot exits with a
message "popen failed" and FileList is not changed.
How to ignore "pope failed" and instead just create an empty plot?

Thank you for any hints.