Pointer argument

First of all, thanks for this great software.

I use my wrapper code in my LUA application, and everything works fine.

Although I'd like to have something like this:

int foo(int a, double *b);

In the C implementation, I'd like to alter the variable b points to,
which is a variable in my LUA code.

I couldn't figure out how to achieve this in my LUA code.

Can you help me realizing this?


Thanks,
Lev