wrap

static VALUE
rb_gzfile_s_wrap(int argc, VALUE *argv, VALUE klass)
{
    VALUE obj = rb_class_new_instance(argc, argv, klass);

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