Connie,

  I don't really know the answer to this, as I have
almost 0 experience with fork, and none within the CGI
context. If this script is called from a web page and
has to wait for something, but you don't know when it
will happen, maybe fork is a good idea, otherwise the
client browser is going to be sitting there for
potentially a long time waiting and not giving back
any response.

  A "zombie" process is one that has been started, but
for one reason or another, can't finish, so it's just
hung there. I'm not a Unix sysadm, and haven't been a
user for quite a while, so I'm a little fuzzy at this
point on exactly what could cause this to happen.

  In fact, I'm fuzzy enough to not even want to give
you an exact definition of what fork does, beyond "it
gives you a second process". So your original process
starts once, you do the fork, and now you have two
processes. I remember there's a little trickiness
involved in getting it to do what you probably want.

  You may have noticed another discussion on this list
talking about fork, it would probably be useful for
you to read it, and any other documentation you can
find. Sounds like a friendly introductory Perl and/or
Unix text would be a good investment for you.

  Good luck!

- John

--- Connie Chan <[EMAIL PROTECTED]> wrote:
> Thousand Thanks, John,
> 
> At lease I get the idea on what I am doing is
> correct.
> 
> "perl -d" is very useful for tracing errors, better
> than log down
> activities.
> and I've test it and found that the "while (! -e
> $result) is not nesssary,
> the
> case is actually A to B, B to C, C to D, and D gen
> reult, then
> D ret null to C , C ret null to B, B return null to
> A,
> and then the open, print, unlink statements.
> 
> What about fork ? In such case, would it be better ?
> or even making more
> trouble ? I've read about perldoc, but still not
> very clear, what are the
> zombie means ? doesn't those vars be removed if the
> script run once
> only ?
> 
> Have a good day =)
> Connie


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