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Author Re: when parent process keeps forking child but doesnot wait...
Bin Chen

2007-04-24, 7:05 pm

On 4=D4=C224=C8=D5, =CF=C2=CE=E712=CA=B116=B7=D6, djh...@gmail.com wrote:
> Hi Unix guru,
>
> In my case, parent receives a request and forks itself and lets the
> child perform a task.
> But parent doesnot wait for child to complete and exit.
> This kind of behavior is normal ,right?
>
> But, when I ps , looks like it displays all those completed and
> exited child processes-->which is bothering me. Do I need to worry
> about it?


Yes, zombie does not consume any resource except some bookkeeping info.

Jens Thoms Toerring

2007-04-25, 10:03 pm

Bin Chen <binary.chen@gmail.com> wrote:
> On 4?24?, ??12?16?, djh...@gmail.com wrote:
[color=darkred]
> Yes, zombie does not consume any resource except some bookkeeping info.


They consume at least one slot in the process table and since
normally there's only a limited number of proceses you can have
at any time (alive or zombies) it's prudent to have them go away,
espcially if the parent is a long-lived program that fork()s a
lot. And it's easy with waitpid() if you call from time to time

while ( waitpid( -1, NULL, NOHANG ) > 0 )
/* empty */ ;

this removes all zombies that exist at that moment and should
consume much time.
Regards, Jens
--
\ Jens Thoms Toerring ___ jt@toerring.de
\__________________________ http://toerring.de
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