#!/usr/bin/perl -w
#ipcprocesses.pm.
...
sub new {
    my $class = shift;
    my $this = { 'field' => 1 };
    bless ($this,$class);
    tie $newvalue,'IPC::Shareable','kali';
    return ($this);
}
...
sub DO_newchild 
   {
    my $this = shift;
   ...
    if ($pid = fork)
    { #parent
        $this->{'field'} = $newvalue;
        ...
    }
    else{
         my $newvalue;
         tie $newvalue,"IPC::Shareable",'kali';
[download]

The $newvalue in DO_newchild masks the outer $newvalue.

If you want the 'field' member to hold a tied variable, tie the value:

sub new {
    my $class = shift;
    #my $this = { 'field' => 1 };
    my $this = { };
    bless ($this,$class);
    tie $this->{'field'},'IPC::Shareable','kali';
    $this->{'field'} = 1;
    return ($this);
}
...
sub DO_newchild 
   {
    my $this = shift;
    if ($pid = fork)
    { #parent
        # $this->{'field'} = $newvalue;
        $num_children++;
        print 'parent '.$$.' | '.$this->{'field'}."\n";
        return;
    }
    else{
         #my $newvalue;
         #tie $newvalue,"IPC::Shareable",'kali';
         #Children can not return from this subroutine
         $SIG{INT} = 'DEFAULT';    #make SIGINT kill us as it did befo
+re
          while(1) {
            sleep 2;
            print 'child '.$$.' | '.$this->{'field'}."\n";
            #$newvalue = time();
            $this->{'field'} = time;
          }
      }
   exit;
}
[download]

That's what you do if you want the 'field' object to be updatable by the parent and child processes, visible to each.

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}