if you're really talking about threads and not processes, the SIGCHLD advice would be rather senseless. in this case you should consider implementing a handler for $SIG{__DIE__} in your main thread and localizing a hook for it in the child threads. e.g.:

# main thread:
sub sig_die_handler {
   my $message = shift;
   warn $message;
}
[...]
# child threads:
local $SIG{__DIE__} = sub { &::sig_die_handler(shift) };
[download]

or something like that. anyway, this is roughly the way to achieve what you have in mind - if we're really talking about threads.