Is completely statifactory to reap all children under all *NIX O/S'es.

$SIG{CHLD} = sub {while (waitpid(-1, WNOHANG) > 0){} };
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This is another way that works on some OS's.

 $SIG{CHLD} = 'IGNORE' # This often works with a few exceptions. 
                          # set 'IGNORE' is fastest if it does work.
                          # But there is something to be said for work
+ing
                          # all the time, albeit slower (see first sol
+ution)
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for those who are interested, the $SIG{CHLD} happens at the sigaction() level. And is faster because no subroutine will be called if the OS supports this option. I am just saying that it is not universally supported.