Hello Bloehdian,

This isn’t an answer to your question, just something I noticed while looking at your code:

...
my $from_parent_one;
my $to_child_one;
my $from_child_one;
my $to_parent_one;

my $from_parent_two;
my $to_child_two;
my $from_child_two;
my $to_parent_two;

my @pipe_handles = ( $from_parent_one,
                     $to_child_one,
                     $from_child_one,
                     $to_parent_one,
                     $from_parent_two,
                     $to_child_two,
                     $from_child_two,
                     $to_parent_two );
...
START: while ( 1 ) {
   ...
   # To be sure possibly remaining open pipe handles
   # are close before creating new ones
   #
   foreach my $handle ( @pipe_handles ) {

      close( $handle ) if defined openhandle( $handle );
         
   }
   ...
[download]

You initialise the array @pipe_handles with the contents of the variables $from_parent_one, $to_child_one, etc. Since these variables have themselves not yet been initialised, @pipe_handles contains (undef, undef, undef, undef, undef, undef, undef, undef) — and is never updated. I assume you intended to store variable references?

my @pipe_handles = \( $from_parent_one,
                      $to_child_one,
                      $from_child_one,
                      $to_parent_one,
                      $from_parent_two,
                      $to_child_two,
                      $from_child_two,
                      $to_parent_two );
...
   foreach my $handle ( @pipe_handles ) {

      close( $$handle ) if defined openhandle( $$handle );
         
   }
[download]

Hope that helps,