embedding octave - passing variables and take them back

[Marco Driusso]

Hello,
I'm trying to embed the octave interpreter into a c++ program, following the octave_embed.tar.gz example (http://wiki.octave.org/wiki.pl?OctaveEmbedded). In this example is explained how to call functions and scripts but not how to pass variables from the c++ ambient to the octave workspace.

The only solutions I've founded are:
1) transform my c++ double arrays to strings and then evaluate them, to pass variables from c++ to octave;
2) save the elaborated variable into a file with the option save(-ascii,..) and read it from the c++ ambient, to pass variables from octave to my c++ program;
but this is not a good solution.

In the help-octave archivie I've founded something like using symbol_table::varref but I don't understand what I've to do.

Could someone explain me how I can push a variable to octave and  also get an octave variable back?
Would be enough to show me how to put a dobule array
double a[length]
in the octave workspace, and how to take back an octave variable to the c++ ambient.

Thanks!
Marco