setpgrp question

[Dan Mercer]

In article <1989Dec24.222740.8645 at virtech.uucp> cpcahil at virtech.uucp (Conor P. Cahill) writes:
:In article <6863 at cbnewsh.ATT.COM>, skumar at cbnewsh.ATT.COM (swaminathan.ravikumar) writes:
:
:> By reading different sources I found out that a process can
:> break its control terminal by calling "setpgrp". I don't
:> understand this 100%. Why should the process lose the control
:> terminal? why do you need "setpgrp"?
:
:setpgrp() is one of the steps that should be executed by a daemon
:process at initialization time.  It does disconnect the terminal from 
:the controll tty and therefore should only be used by programs that
:no longer wish to be associated with a terminal.

For instance,  in the telecommunications program PCOMM,  patterned
closely after PROCOMM(tm),  the input process originally generated
SIGHUP back to the controlling terminal when the dial-out line hung
up.  I was one of the first to notice the problem,  since I have
a personal daemon running in background that provides me special
services within vi.  Adding a setpgrp() to the input routine cleared
the problem and was later added by a patch level.

The Token Ring NetBIOS software for the NCR Tower has the same problem
with nlogin,  which allows login sessions across the ring.


-- 

Dan Mercer
Reply-To: mercer at ncrcce.StPaul.NCR.COM (Dan Mercer)