4.2 oddity -- SLOGIN flag in proc.h

[Stephen Crawley]

While writing a program which uses various bits of information from
the proc table, I found the following oddity.

The <sys/proc.h> header file contains the following line :-

#define	SLOGIN	0x0800000	/* a login process (legit child of init) */

However, ps -axl indicates that this bit is not set for any processes.
Indeed, grepping /sys/sys confirmed that SLOGIN isn't referenced anywhere.
While making sure that the flag gets set would seem to be straight forward,
I'm not convinced that it would be stunningly useful.  [ What would be
more useful would be if the login shell pid were recorded in /etc/utmp! ]

I was wondering what this all means.  Is this something that the 4.2
implementors dropped as being a bad idea?  Or something that didn't get 
finished in time?  Are all login processes under 4.2 illegitimate??  :-) :-)

			Stephen C. Crawley

ARPA:	scc%cl.cam.ac.uk at ucl-cs.ARPA  SMail: Cambridge Univ. Computer Lab.,
JANET:	scc at uk.ac.cam.cl                     Corn Exchange Street,
UUCP:	{ukc,kcl-cs}!cl-jenny!scc	     Cambridge CB2 3QG, 
PHONE:	+44 223 352 435                      England.

p.s. No prizes for guessing what the program is supposed to do.