catchpoint= (Debugger)

    /*
     *   call-seq:
     *      Debugger.checkpoint = string -> string
     *
     *   Sets checkpoint.
     */
    static VALUE
    debug_set_catchpoint(VALUE self, VALUE value)
    {
        debug_check_started();

        if (!NIL_P(value) && TYPE(value) != T_STRING) {
            rb_raise(rb_eTypeError, "value of checkpoint must be String");
        }
        if(NIL_P(value))
        catchpoint = Qnil;
        else
        catchpoint = rb_str_dup(value);
        return value;
    }