vector_base
msg->schemes = vector_base(offset, count, GUID_LENGTH, msg_base, msg_len);
p = vector_base(offset, count, EXTENSION_LENGTH, msg_base, msg_len);
p = vector_base(offset, len, 1, msg_base, msg_len);
msg->cksum = vector_base(offset, len, 1, msg_base, msg_len);
p = vector_base(alerts_offset, nalerts, ALERT_LENGTH, msg_base, msg_len);
p = vector_base(value_offset, value_len, 1, msg_base, msg_len);