> -----Original Message-----
> From: Mayank Ahuja [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, July 23, 2002 3:15 AM
> To: Perl
> Subject: Can IPC work?
>
>
> Hi All,
>
> Please go through the following scenario:
>
> A perl script has been invoked from shell A. Within the perl script, I
> open a new terminal (say B) allowing the user set a
> particular variable
> to his choice. The user sets the variable in this terminal
> and will exit
> the terminal so that the perl script continues to work.
>
> Putting it graphically,
>
>
> A
> |
> |
> |-------
> | |
> | B
> | (New Terminal)
> | [User sets a variable]
> |
> |
> (execution of the script continues once B is over)
>
>
> Is there a way by which Shell A can come to know of the value of the
> variable set in B?
> I don't know anything about IPC...can it work in this scenario?
I assume by "new terminal" you mean a shell invoked by system() or
similar, correct?
Given that, there is no direct way for process B to update the
environment of process A. The two must cooperate to make this happen.
Your options are:
1. A can retrieve B's exit status, which is a number.
2. B can send a signal to A, which A can handle.
3. B can write some information to a file, which A can later read.
4. B can talk to A through some IPC mechanism: pipes, sockets, shared
memory, message queues, etc.
Some shells may allow you to set up an action to happen when the shell
exits; this may be a hook where you can write the environment to a file
or pipe in order to pass information back to A. Such a mechanism could
probably be defeated rather easily though...
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