Re^2: Killing process group run with IPC::Open3


Hi ikegami,

That's a good point and infact I tried exec first (that's why use of setpgrp).  But problem is I also need to capture <stdin> in my app. Here is example:

> cat app.pl
print "continue? "; $yesno=<STDIN>; print "--$yesno";

> perl fixed.pl 5 perl -e 'system("perl app.pl")'
continue? y
alarmed out
sent kill signal to 1
^C

> perl test.pl 5 perl -e 'system("perl app.pl")'
continue? y
--y
Child exit status: 0 signal: 0

Is there any way to map <STDIN> in fixed.pl ?

Comment on Re^2: Killing process group run with IPC::Open3

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Re^3: Killing process group run with IPC::Open3 by ikegami (Patriarch) on Feb 03, 2012 at 07:22 UTC
So I ran a few tests. It seems that the child can't read from the parent's STDIN. I presume this is the problem to which you are referring. `man 2 setpgrp` explains At any time, one (and only one) of the process groups in the session can be the foreground process group for the terminal; the remaining process groups are in the background. I don't know what a session is, but adding `setsid()` appears to solve the problem.	[reply] [d/l] [select]
Re^4: Killing process group run with IPC::Open3 by pm_sanchay (Initiate) on Feb 03, 2012 at 07:49 UTC
My bad for using pre. I will be more careful from now. Yes, I meant "child can't read from the parent's STDIN". `setsid()` does appear to work. But it has another issue - I don't understand what happens if a KILL signal is sent to parent (example cntl-c)? Will have to understand what setsid does. Thanks for your help.	[reply] [d/l]
Re^3: Killing process group run with IPC::Open3 by ikegami (Patriarch) on Feb 03, 2012 at 07:06 UTC
Capture an input? Your terminology makes no sense to me. What do you mean by "capture `<stdin>`"? Whatever it is you want to do, if you know how to do it with `open3`, keep doing it that way. There's nothing special about "fixed.pl" on that side of things. PS — Please don't use `<pre>`. At all. Place code, computer text, inputs, outputs, etc in `<code></code>` or `<c></c>` tags. And use `<p>` at the start of paragraphs.	[reply] [d/l] [select]