expectperl-discuss

[Expectperl-discuss] unExpected problems

[<mos...@po...>]

Greetings,
I have compiled in Expect  and dependent modules into perl,
but can't get even the simplest example script to run.
We are running perl on HP-UX10 on a HP-N1000 system.
When I debug it I get the following error:

spawn(/opt/perl5/lib/site_perl/5.005/Expect.pm:110):
110:      unless (defined ($pid)) {
  DB<1> Expect::spawn(/opt/perl5/lib/site_perl/5.005/Expect.pm:110):
110:      unless (defined ($pid)) {
######### Forked, but do not know how to change a TTY. #########
  Define $DB::fork_TTY
       - or a function DB::get_fork_TTY() which will set $DB::fork_TTY.
  The value of $DB::fork_TTY should be the name of TTY to use.
  On UNIX-like systems one can get the name of a TTY for the given window
  by typing tty, and disconnect the shell from TTY by sleep 1000000.

Then perl hangs on the following line:
$self->make_slave_controlling_terminal();

Does anyone out there have any ideas?
Kind regards,
Michael Osborne
Queensland Medical Laboratory
Information Technology Officer

These opinions are my own and may not represent those of my employers.


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Re: [Expectperl-discuss] unExpected problems

[Simon T. <si...@un...>]

Hello Michael,

> I have compiled in Expect  and dependent modules into perl,
> but can't get even the simplest example script to run.
> We are running perl on HP-UX10 on a HP-N1000 system.
> When I debug it I get the following error:
>
> spawn(/opt/perl5/lib/site_perl/5.005/Expect.pm:110):
> 110:      unless (defined ($pid)) {
>   DB<1> Expect::spawn(/opt/perl5/lib/site_perl/5.005/Expect.pm:110):
> 110:      unless (defined ($pid)) {
> ######### Forked, but do not know how to change a TTY. #########

Very odd. I have used Expect.pm in HP-UX 10.20 on one clients' site with no 
problems.

I know that pty allocation is a bit of a black art, so maybe you are running 
into something specific to your environment.

Have you tried:

  * Running the same test script as the root user (assuming that this is
    possible for you). This once helped narrow down a similar pty issue for me 
    in FreeBSD, where, for some reason, I could not allocate pty's unless I
    was the super-user. 

  * Using the tcl expect tool to debug, ie: if you happen to have the "expect"
    program installed on your machine, you can just type "expect" and when
    it gives you a prompt, enter "spawn sh". If pty allocation is OK on your
    machine, then this test should return a process id. Then at least you 
    would know that the problem was with your Expect.pm implementation.

  * Try a *really* simple test in perl, such as:

    perl -MExpect -e '$e = Expect->spawn("sh") ; print $e->pid()'

    On my system, this returns a PID.

Good luck.

Regards,

Simon Taylor
-- 
Unisolve Pty Ltd - Melbourne, Australia
+61 3 9568 2005