global objects in C

["Keisuke Nishida" <kei@psn.net>]

Hi,

I would like to manage some scheme objects by global variables in C.
That is, I would like to write like this:

SCM global_stack;

init_global_stack ()
{
  global_stack = SCM_EOL;
}

stack_push (SCM obj)
{
  global_stack = scm_cons (obj, global_stack);
}

stack_pop ()
{
  SCM obj = SCM_CAR (global_stack);
  global_stack = SCM_CDR (global_stack);
  return obj;
}

I suppose I have to protect the variable global_stack from GC
by pointer, like:

  scm_protect_pointer (&global_stack);

before using global_stack.  Is there any way to do this?

Also, I would like to connect global_stack and a scheme symbol
`global-stack' seamlessly.  That is, "global_stack = ...;" in C
changes the value of global-stack, and "(set! global-stack ...)"
in Scheme changes the value of global_stack.  I guess I can do
this by modifying the evaluater, as Emacs does, but I wonder if
there is already excellent way to do that.

Thanks in advance.