How to get Lua functions address?

["jose_marin2 <jose_marin2@...>" <jose_marin2@...>]

Hi!

I want to do something like this:


I Lua file:

---------------------------------

function KeyFunc(key)
.
.
.
end

SetKeyFunction(KeyFunc)

---------------------------------


SetKeyFunction is a C function. It must to get the address of the 
function and store it in a variable.
Then, when the user press a key, I must call this func (KeyFunc) with 
a parameter (the key pressed).

I have 2 problems: 
1 - how to get and store a Lua function address in a C variable and
2 - how to call it with a parameter from C code.

Any tip?

Thanks in advance

José