[Gnuplot-info] system independent access to home folder and script folder?

Does Gnuplot offer a system independent way to
create directory names relative to the home folder (especially)
and also relative to the script folder?

I am aware of `system`, but that depends on the OS shell.
I'm not a C programmer, but I believe the tricks to retrieve this
information in a system independent way are pretty standard. (?)

Thank you.