Monitoring variables of a running script from c

[Stevo <steve.bn@...>]

Hello,
i am developing a small application for controlling a robot unit. In  
this program is use lua to run scripts which move the robot by calling  
the functions of the c program. This works fine but now i would like  
to implement a variable monitor, to display the value of e.g. the  
counter of a for-loop in the GUI of the c-program.

The easiest implemetation for me would be to pass another c-function  
to lua which can be added in the script to pass the value of the  
desired variable and update the view. But this is also the least  
elegant solution ;)

I read a bit into the lua-debug-facilities but i did not really  
understand if monitoring variables is possible with it.

The third thing is the variable lua_getglobal. Is it possible to call  
it periodically in the C-programm while the script is running? I read  
the function takes the variable from the stack so i guess it is only  
valid to call lua_getglobal when the skript has finished?

Thanks in advance for your help!
(and sorry for my bad english ;)

Greeting
 Steve