All I am reading Network Programming with Perl by Lincoln Stein. I am having trouble on page 443, "Handling HUP and other Signals", here's a snip of the code which I am having trouble with, 
sub reap_child {
   while ( (my $child = waitpid(-1,WHNOHANG)) > 0) {
      $CHILDREN{$child}->($child) if ref $CHILDREN{$child} eq 'CODE';
      delete $CHILDREN{$child};
   }
}

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what's does this line do,  $CHILDREN{$child}->($child) if ref $CHILDREN{$child} eq 'CODE'? Is it saying $CHILDREN{$child} = $child if ref $CHILDREN{$child} eq 'CODE'? What does the value 'CODE' means? 
sub kill_children {
   kill TERM => keys %CHILDREN;
   sleep while %CHILDREN;
}

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what does </code>"kill TERM => keys %CHILDREN;"</code> mean? Send a Kill TERM signal to all children pid? Not use to seing "TERM => (value ... values + n". Thanks.

In reply to Bulletproofing Servers by perlknight

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