EXCESS_3_2_LEN
return(peek3_2(md->readfd) - EXCESS_3_2_LEN);
size = stoh(msgbuf + HEAD_SIZE) - EXCESS_3_2_LEN;
char tmpbuf [MSGMAX + EXCESS_3_2_LEN];
(void) htos(tmpbuf + HEAD_SIZE, size + EXCESS_3_2_LEN);
rval = write_fifo(md->writefd, tmpbuf, size + EXCESS_3_2_LEN);