reading Mail with more

[tektronix!zehntel!varian!david]

A few weeks ago I asked if anyone had ever solved the problem of reading
long messages (more than one screenful) in Mail (Berkeley Mail).
I didn't receive any replies, so I went ahead and did it myself. Now when
reading mail, if the article is longer than 23 lines, it gets piped through
more.
The change was quite simple, though one could make it fancier (get PAGER and
PAGESIZE from the environment or from .mailrc and /usr/lib/Mail.rc, etc.).  
I have made this change on both our VAX 11/780 running 4.1BSD and our 
PDP11/70 running 2.8BSD; we've been running it for several days without
problems.  I'd appreciate hearing any comments or problems anyone may
encounter.

While looking through the code, I discovered an undocumented command:
	z+ will display the next page of the table of contents
	z- will display the previous page
This is of use only if you have more than 18 articles in your mail queue.

	David Brown
	Varian Instruments
	2700 Mitchell Dr.
	Walnut Creek, Ca. 94598
	(415) 939-2400
	...!decvax!sytek!zehntel!varian!david
	...!ucbvax!menlo70!sytek!zehntel!varian!david
	...!tektronix!zehntel!varian!david
	...!fortune!varian!david

-------

In /usr/src/cmd/ucbmail/cmd1.c:

in routine print():
change at line 227:
 	send(mp, stdout);
to:
 	sendpage(mp, stdout);

and add at the end a new routine sendpage(), which is a modification
of the send routine in send.c:

#define PAGER "/usr/ucb/more"
#define PAGESIZE 23
sendpage(mailp, obuf)
	struct message *mailp;
	FILE *obuf;
{
	register struct message *mp;
	register int t;
	unsigned int c;
	FILE *ibuf;
	int lc;
	FILE *pfp, *popen();

	mp = mailp;
	ibuf = setinput(mp);
	c = msize(mp);
	if (mp->m_lines > PAGESIZE) {
		fflush(obuf);
		pfp = popen(PAGER,"w");
		if (pfp == NULL)
			pfp = obuf;
	}
	else
		pfp = obuf;
	while (c-- > 0) {
		putc(t = getc(ibuf), pfp);
		if (t == '\n')
			lc++;
	}
	if (pfp != obuf)
		pclose(pfp);
	return(lc);
}