Function: variable-binding-locus

variable-binding-locus is a function defined in data.c.

Signature

(variable-binding-locus VARIABLE)

Documentation

Return a value indicating where VARIABLE's current binding comes from.

If the current binding is buffer-local, the value is the current buffer. If the current binding is global (the default), the value is nil.

Source Code

// Defined in /usr/src/emacs/src/data.c
{
  struct Lisp_Symbol *sym;

  CHECK_SYMBOL (variable);
  sym = XSYMBOL (variable);

  /* Make sure the current binding is actually swapped in.  */
  find_symbol_value (variable);

 start:
  switch (sym->u.s.redirect)
    {
    case SYMBOL_VARALIAS: sym = indirect_variable (sym); goto start;
    case SYMBOL_PLAINVAL: return Qnil;
    case SYMBOL_FORWARDED:
      {
	lispfwd valcontents = SYMBOL_FWD (sym);
	if (KBOARD_OBJFWDP (valcontents))
	  return Fframe_terminal (selected_frame);
	else if (!BUFFER_OBJFWDP (valcontents))
	  return Qnil;
      }
      FALLTHROUGH;
    case SYMBOL_LOCALIZED:
      /* For a local variable, record both the symbol and which
	 buffer's or frame's value we are saving.  */
      if (!NILP (Flocal_variable_p (variable, Qnil)))
	return Fcurrent_buffer ();
      else if (sym->u.s.redirect == SYMBOL_LOCALIZED
	       && blv_found (SYMBOL_BLV (sym)))
	return SYMBOL_BLV (sym)->where;
      else
	return Qnil;
    default: emacs_abort ();
    }
}