Re: Re: Fork novice requests help...Part Deux

Greetings all,

I can't seem to get this thing to work! Can wait be called in such a way that the parent is made aware of the presence of children? What I want to do is something similar to this:

foreach $letter (x','y','z'){
 foreach $number (1 .. 5){
if (wait() != -1){
 if ($pid = fork){
  print "Forking for $letter, $number\n";
  sleep 15;
  exit;
 }}}}
[download]

I know that this doesn't work as I've written it. What I would like for the code above to do is to fork off children for 'x' at the same time, wait for all of those children to finish, and only then, start forking off children for 'y'. Is there any way to do this?

Thanks in advance,
thor

Comment on Re: Re: Fork novice requests help...Part Deux Download Code

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Re: Fork novice requests help...Part Deux by Abigail (Deacon) on Jun 26, 2001 at 21:42 UTC
I think you mean something like this: #!/opt/perl/bin/perl -w use strict; my %kids; foreach my $letter ('x' .. 'z') { print localtime () . ": Forking kids for $letter\n"; foreach my $number (1 .. 5) { my $code = "$letter$number"; my $pid = fork; die "Failed to fork $code" unless defined $pid; $kids {$pid} = [$code, time] if $pid; unless ($pid) { # In child. my $sleep = 2 + int rand 18; print localtime () . ": Kid $code sleeping for $sleep seconds.\n"; sleep $sleep; exit; } } while ((my $kid = wait) != -1) { print localtime () . ": Reaped kid $kids{$kid}->[0] after ", time () - $kids {$kid} -> [1], " seconds.\n"; } print localtime () . ": Done reaping kids for $letter\n"; sleep 1; } __END__ [download] Running this produces: Tue Jun 26 19:40:41 2001: Forking kids for x Tue Jun 26 19:40:42 2001: Kid x5 sleeping for 7 seconds. Tue Jun 26 19:40:42 2001: Kid x2 sleeping for 9 seconds. Tue Jun 26 19:40:42 2001: Kid x1 sleeping for 10 seconds. Tue Jun 26 19:40:42 2001: Kid x3 sleeping for 11 seconds. Tue Jun 26 19:40:42 2001: Kid x4 sleeping for 15 seconds. Tue Jun 26 19:40:49 2001: Reaped kid x5 after 7 seconds. Tue Jun 26 19:40:51 2001: Reaped kid x2 after 9 seconds. Tue Jun 26 19:40:52 2001: Reaped kid x1 after 10 seconds. Tue Jun 26 19:40:53 2001: Reaped kid x3 after 11 seconds. Tue Jun 26 19:40:57 2001: Reaped kid x4 after 15 seconds. Tue Jun 26 19:40:57 2001: Done reaping kids for x Tue Jun 26 19:40:58 2001: Forking kids for y Tue Jun 26 19:40:58 2001: Kid y4 sleeping for 4 seconds. Tue Jun 26 19:40:58 2001: Kid y3 sleeping for 4 seconds. Tue Jun 26 19:40:58 2001: Kid y5 sleeping for 7 seconds. Tue Jun 26 19:40:58 2001: Kid y2 sleeping for 8 seconds. Tue Jun 26 19:40:58 2001: Kid y1 sleeping for 10 seconds. Tue Jun 26 19:41:02 2001: Reaped kid y4 after 4 seconds. Tue Jun 26 19:41:02 2001: Reaped kid y3 after 4 seconds. Tue Jun 26 19:41:05 2001: Reaped kid y5 after 7 seconds. Tue Jun 26 19:41:06 2001: Reaped kid y2 after 8 seconds. Tue Jun 26 19:41:08 2001: Reaped kid y1 after 10 seconds. Tue Jun 26 19:41:08 2001: Done reaping kids for y Tue Jun 26 19:41:09 2001: Forking kids for z Tue Jun 26 19:41:09 2001: Kid z5 sleeping for 2 seconds. Tue Jun 26 19:41:09 2001: Kid z2 sleeping for 5 seconds. Tue Jun 26 19:41:09 2001: Kid z4 sleeping for 6 seconds. Tue Jun 26 19:41:09 2001: Kid z1 sleeping for 11 seconds. Tue Jun 26 19:41:09 2001: Kid z3 sleeping for 12 seconds. Tue Jun 26 19:41:11 2001: Reaped kid z5 after 2 seconds. Tue Jun 26 19:41:14 2001: Reaped kid z2 after 5 seconds. Tue Jun 26 19:41:15 2001: Reaped kid z4 after 6 seconds. Tue Jun 26 19:41:20 2001: Reaped kid z1 after 11 seconds. Tue Jun 26 19:41:21 2001: Reaped kid z3 after 12 seconds. Tue Jun 26 19:41:21 2001: Done reaping kids for z -- Abigail	[reply] [d/l]
Re: Re: Fork novice requests help...Part Deux by thor (Priest) on Jun 27, 2001 at 00:27 UTC
YES!!! Note to self: buy Abigail a Christmas present! Thank you very much. I couldn't for the life of me figure this one out.	[reply]