dump( obj [, anIO] , limit=--1 ) → anIO

Serializes obj and all descendent objects. If anIO is specified, the serialized data will be written to it, otherwise the data will be returned as a String. If limit is specified, the traversal of subobjects will be limited to that depth. If limit is negative, no checking of depth will be performed.

class Klass
  def initialize(str)
    @str = str
  end
  def sayHello
    @str
  end
end

(produces no output)

o = Klass.new("hello\n")
data = Marshal.dump(o)
obj = Marshal.load(data)
obj.sayHello   #=> "hello\n"

Source Code

/*
* call-seq:
*      dump( obj [, anIO] , limit=--1 ) => anIO
*
* Serializes obj and all descendent objects. If anIO is
* specified, the serialized data will be written to it, otherwise the
* data will be returned as a String. If limit is specified, the
* traversal of subobjects will be limited to that depth. If limit is
* negative, no checking of depth will be performed.
*
*     class Klass
*       def initialize(str)
*         @str = str
*       end
*       def sayHello
*         @str
*       end
*     end
*
* (produces no output)
*
*     o = Klass.new("hello\n")
*     data = Marshal.dump(o)
*     obj = Marshal.load(data)
*     obj.sayHello   #=> "hello\n"
*/
static VALUE
marshal_dump(argc, argv)
   int argc;
   VALUE* argv;
{
   VALUE obj, port, a1, a2;
   int limit = -1;
   struct dump_arg arg;
   struct dump_call_arg c_arg;

   port = Qnil;
   rb_scan_args(argc, argv, "12", &obj, &a1, &a2);
   if (argc == 3) {
       if (!NIL_P(a2)) limit = NUM2INT(a2);
       if (NIL_P(a1)) goto type_error;
       port = a1;
   }
   else if (argc == 2) {
       if (FIXNUM_P(a1)) limit = FIX2INT(a1);
       else if (NIL_P(a1)) goto type_error;
       else port = a1;
   }
   arg.dest = 0;
   if (!NIL_P(port)) {
       if (!rb_respond_to(port, s_write)) {
         type_error:
           rb_raise(rb_eTypeError, "instance of IO needed");
       }
       arg.str = rb_str_buf_new(0);
       arg.dest = port;
       if (rb_respond_to(port, s_binmode)) {
           rb_funcall2(port, s_binmode, 0, 0);
       }
   }
   else {
       port = rb_str_buf_new(0);
       arg.str = port;
   }

   arg.symbols = st_init_numtable();
   arg.data    = st_init_numtable();
   arg.taint   = Qfalse;
   c_arg.obj   = obj;
   c_arg.arg   = &arg;
   c_arg.limit = limit;

   w_byte(MARSHAL_MAJOR, &arg);
   w_byte(MARSHAL_MINOR, &arg);

   rb_ensure(dump, (VALUE)&c_arg, dump_ensure, (VALUE)&arg);

   return port;
}