rb_gc_register_address 1991 ext/readline/readline.c     rb_gc_register_address(&readline_instream);
rb_gc_register_address 1992 ext/readline/readline.c     rb_gc_register_address(&readline_outstream);
rb_gc_register_address 6147 gc.c               rb_gc_register_address(var);
rb_gc_register_address 1714 include/ruby/ruby.h void rb_gc_register_address(VALUE*);