Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: $Revision: 1.6.2.16 $; site haddock.UUCP
Path: utzoo!watmath!clyde!cbosgd!ulysses!allegra!mit-eddie!genrad!panda!talcott!harvard!bbnccv!haddock!rob
From: rob@haddock.UUCP
Newsgroups: net.news.notes
Subject: Re: Nfxmit core
Message-ID: <102300001@haddock.UUCP>
Date: Sun, 12-Jan-86 20:04:00 EST
Article-I.D.: haddock.102300001
Posted: Sun Jan 12 20:04:00 1986
Date-Received: Tue, 14-Jan-86 05:55:50 EST
References: <4600001@wvlpdp.UUCP>
Lines: 43
Nf-ID: #R:wvlpdp:4600001:haddock:102300001:000:1591
Nf-From: haddock!rob    Jan 12 20:04:00 1986


[Take that! And That!  Don't take this!  Take the other thing!]

john@wvldpdp (John A. Ebersold) wonders why nfxmit dumps core when
queueing large notefiles.  The answer almost certainly is a
16-bits-ain't-enough coding error in recsio.c.
Here is an excerpt from my copy of recsio.c:
(Dont forget to fix all 4 instances of this bug!)

/*
 * In all of {get,put}{n,r}rec below, explicitly cast one
 * of the members of the rhs of the "where" assignment
 * to long.  This prevents a problem in 16 bit machines
 * whereby
 *	sizeof (*descr) + n * sizeof (*note)
 * is evaulated thusly:
 *	<long> = <int> + <int> * <int>
 * i.e.	<long> = <int>
 * thus losing some of the information.  You will have this
 * problem on your machine as soon as "n * sizeof (*not)" exceeds
 * MAXINT  (or maybe MAXUNSIGNED.)
 */

getnrec (io, n, note) struct note_f *note;		/* n is the number of the note to get.  0 is policy note */
struct io_f *io;
{
    long    where;					/* going to seek here eventually */
    struct descr_f *descr;				/* for sizeof below */

    x (n < 0, "getnrec: negative recnum");
#if	0
    where = sizeof (*descr) + n * sizeof (*note);
#else
    where = sizeof (*descr) + (long)n * sizeof (*note);
#endif
    x (lseek (io -> fidndx, where, 0) < 0, "getnrec: seek");
    x (read (io -> fidndx, note, sizeof *note) < sizeof *note, "getnrec: read");
}

Rob Adams {decvax ! cca | yale | ihnp4 | cbosgd}!ima!rob
{bbncca | harvard | zurton | cfib | mit-ems | wjh12 }!ima!rob
{uscvax | ucla-vax | vortex}!ism780!rob
Interactive Systems, 7th floor, 441 Stuart st, Boston, MA 02116; 617-247-1155