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!
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