Questions on using prgma Import (C, foo)

[pfpearson.net@gmail.com]

I'm writing some Ada bindings for lua ( http://www.lua.org/ ), a very
small and fast interpreter with a clean C API.  While I've been
developing Ada for years, this is my first real foray into importing C
libraries (I've done the occasional import of memcpy() or such).

My question is how to handle C functions that return "char *".  The
Lua function is question is:
     const char *lua_tolstring (lua_State *L, int index, size_t *len);

At first I just wrote this as:
  function lua_tolstring (L: lua_State_ptr; index: inteter; len :
size_t_ptr) return Interfaces.C.Char_array;

However, it only took me a minute to realize that this won't work.
I see two options:
1. function lua_tolstring (...) return System.Adddress;
2. use the types declared in Interfaces.C.Strings.

Has anyone else been down this path?  If so, can you share your
experiences?

I've read the AARM, and done some Googling, and looked through the
sources in Gnat.  If you want me to RTFM, then please point me to the
manual, and I will gladly read it!

thanks!