Dear Ben,
Thanks for the detailed reply to my query.
If my questions below can be answered by online docs, please feel free
to point me to them. I read through the following docs before my
previous email. But I am still mostly in the dark:
* "man -s 2" for fork(), wait(), waitpid() and kill()
* "perldoc -f" for fork(), wait(), waitpid() and kill()
* "perldoc perlipc"
> 1 until -1 == wait();
>
> You'll need something more complex if you want to track the children's
> exit statuses (very useful for debugging).
That idiom is good to know. But I *do* need to track exit statuses
(stati?). Please see my pseudo-code below.
> If you [use POSIX] you can
>
> $kid = waitpid(-1, WNOHANG);
>
> to poll to see if a kid needs to be reaped. [...]
I've seen this verb "reap" in this context, but don't know what it
means. When and how do I "reap" a kid? How is "reaping" different
from kill()ing it?
> Rather than worry about whether you are a child/parent for the rest of
> your code, I usually put an exit() here. [...]
Sorry, I don't follow at all.
> Explicitly managing children and forking tends to be a lot of work.
> Unless you really need the complexity, I find that it tends to be
> easier to take the "poor man's" approach and do system calls and open
> up pipes.
I'd much rather do system calls, if I can figure out how to wait for
the children to finish up.
All I really want is:
system("something $_ &") for 1..5;
&wait_for_all_children; # "1 until -1 == wait;" might suffice.
&compute_summary_of_children_activities;
But that won't really work, will it? system("something $_ &") will
launch "something" as a background job, and then come back in a flash
to tell me that I don't have any child. So &wait_for_all_children
won't have anything at all to wait for.
peace, || No Coke at University of Michigan:
--{kr.pA} || http://tinyurl.com/cbdal
--
How do you spell "unwritten rule"?
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