[Info-vax] login information capture

[George Cornelius]

Gotfryd Smolik wrote:
> On Tue, 18 Feb 2014, Stephen Hoffman wrote:
> 
>> $ if f$mode() .eqs. "INTERACTIVE"
>> $ then
>> $   read/prompt="Why are you here? " sys$command reason
> 
> 
>  Ensures occurrence of Murphy's laws.
>  Paul goes on vacation, someone tries X-windows session :)
>  Interactive session does not mean "terminal session" (not only).
> 
>  IMO the only safe resolution is a double IF: one checking for existence
> of "TT:" *or* interactive mode, and second for DEVCLASS of TT:
> 
> $ if f$getdvi("TT:","EXISTS") then -    ! or: $ if
> f$mode().eqs."INTERACTIVE")
>     if f$getdvi("TT:","DEVCLASS").eq.66 then [...the action...]
> 
>  Preventing the question - in detached mode "TT" is not defined.
>  Yes, checked sometime also by Murphy law ;>
> 
> best regards, Gotfryd

Amazing how many things can go wrong in the login command procedures;
especially true for SYS$SYLOGIN. For X window sessions, you generally
do not want to exit with an error status, so it is not uncommon to
end with the command $ EXIT 1.

I generally check SYS$COMMAND and not "TT", but I'm not sure there's
a difference.  I believe I use

  $ IF F$MODE().EQS."INTERACTIVE" THEN -
  $   IF F$GETDVI("SYS$COMMAND","TRM") THEN -
        [...]

or an equivalent.

In the case of a $ READ/PROMPT, adding /ERROR=... is probably a
good idea, even if all it does is substitute a default response
string when the read op fails.  And if no data is provided you
may want to just loop back and ask again.

George