info-vax@ucbvax.ARPA (02/28/85)
From: engvax!KVC@cit-vax
Does anyone out there know how to cancel a terminal IO request when
the request happens to be on a channel number that you do not have?
The application is this:
I have written a program to perform the (undocumented so far as I know)
IO$_SETMODE!IO$M_TT_DISCON function to terminals that are on the system
and idle. I figure it'd be a lot nicer to disconnect the guy that forgot
to log out than to simply waste-his-ass... If you aren't the type of
system manager that likes to be nice to the choad that forgot to log out, then
the program has it's other uses (like you logged in in the machine room to
read a tape and then walked over to your office and when the tape finishes you'd
like to disconnect the terminal in the machine room and reconnect to that
job from your office...)
In any case, the program works just fine now, thanks to the SHARE privilege,
but the SETMODE QIO hangs if the other process has any sort of outstanding
read (probably would with write as well) request. Now, $CANCEL won't work
since the channel number you supply is not the channel number the request
is on (unless $CANCEL can do something I don't know about...).
So, anyone got any magic for this one? I realize that there may be cases where
whatever you do to the other person's QIO may cause something odd to occur
when he reconnects to his job, but even that'd be ok in the general case where
the read request came from DCL and DCL will just re-issue the read.
/Kevin Carosso engvax!kvc @ CIT-VAX.ARPA
Hughes Aircraft Co.
ps. Anyone know the difference between the IO function modifiers
[IO$M_TT_DISCON, IO$M_TT_CON] and the similarly named (but
different bits) [IO$M_DISCONNECT, IO$M_CONNECT]? I used the
_TT_ set and it seems to work.