Ahmed Moustafa <[EMAIL PROTECTED]> wrote:
> From: "Bob Showalter" <[EMAIL PROTECTED]>
[ waitpid() in tight loop ]
>> This example is straight out of perldoc -f waitpid, but if it's
>> used "as-is", I don't see the point. Why do a non-blocking wait,
>> when the do loop effectively blocks the program anyway. You only
>> want non-blocking when you have something else to do.
>> I would write the above as:
>>
>> 1 while wait != -1; # wait for all children
>>
>> Or am I missing something?
>
> All I need to do is to reap the dead processes without blocking
> the program. (Also I don't want to ignore the children with using
> $SIG{CHLD} = 'IGNORE';).
Why not? I mean, I admire dedicated parents, but (most) *nix
systems will reap them *for you* if you ignore SIGCHLD.
#!/usr/bin/perl
$SIG{CHLD} = 'IGNORE';
fork || exit for 1..100;
sleep 2;
print "waited $x\n" until ($x = wait) == -1;
print "Done!\n";
If your flavor doesn't support this then you'll usually wait()
in the signal handler:
#!/usr/bin/perl
$SIG{CHLD} = sub { wait };
...
But in general, unless you're going to do something useful with
the exit status, $SIG{CHLD} = 'IGNORE' is exactly what you want.
--
Steve
perldoc -qa.j | perl -lpe '($_)=m("(.*)")'
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