http://www.perlmonks.org?node_id=285088

xiper has asked for the wisdom of the Perl Monks concerning the following question:

I have a parent that spawns a bunch of children, up to 10 at any one time, to do some 'mostly-idle' processing. My question is, how to i get the results back from each child? Previously i've used the exit status of the child, which is fine for simple return values, but now i have a complex-data-structure to be returned (although can easily be encoded into a string by Data::Dumper if necessary). I've experimented with pipes but they only seem to work with 1 parent - 1 child relationship. IPC::Shareable looks to do what i want, but i wanted to get input from others to see if there was a simpler solution.

My code so far, if anyone's interested:

my( %pid ); foreach my $num ( "01" .. "25" ) { # if max processes, wait for one to finish if( keys( %pid ) >= 10 ) { &reap() } if( my $pid = fork() ) # parent { $pid{$pid} = $num; } else # child { &child( $num ); exit 0; } } # reap remaining processes while( %pid ) { &reap() } # <collect data> sub reap { my( $pid ) = wait(); if( $pid == -1 ) { die( "no more kids to reap!\n" ) } if(! $pid{$pid} ) { die( "why did I see $pid?\n" ) } delete( $pid{$pid} ); } sub child { my( $num ) = $_[0]; print "child $num spawned\n"; # <send data> }

Thanks all!

- ><iper

my JAPH: print"Just another Perl hacker\n"; # ^ look, no space! pretty tricky huh?