SDC_HDRLEN
#define SDC_BUFLEN(un) (SDC_HDRLEN(un) + MODE_BLK_DESC_LENGTH + \
int hdrlen = SDC_HDRLEN(un);
int hdrlen = SDC_HDRLEN(un);
int hdrlen = SDC_HDRLEN(un);
int hdrlen = SDC_HDRLEN(un);