open

static VALUE
fsdbm_s_open(int argc, VALUE *argv, VALUE klass)
{
    VALUE obj = Data_Wrap_Struct(klass, 0, free_sdbm, 0);

    if (NIL_P(fsdbm_initialize(argc, argv, obj))) {
        return Qnil;
    }

    if (rb_block_given_p()) {
        return rb_ensure(rb_yield, obj, fsdbm_close, obj);
    }

    return obj;
}