#!/usr/bin/perl -w
use strict;
[...] # use whatever else
use threads;
use threads::shared;
use Thread::Queue;
[...]
sub logger;
our ($logs, $logger);
$logs = Thread::Queue->new;
$logger = threads->new(\&logger, "/path/to/logfile");

our $DEBUG : shared = 1;

# care for signals:
$SIG{INT} = $SIG{QUIT} = $SIG{CONT} = $SIG{STOP} =
$SIG{TSTP} = $SIG{CHLD} = $SIG{TRAP} = $SIG{USR1} =
$SIG{TTIN} = $SIG{TTOU} = $SIG{VTALRM} = $SIG{ALRM} = \&sig_ignore;
$SIG{PIPE} = \&sig_pipe;
$SIG{BUS} = $SIG{ILL} = $SIG{SEGV} = $SIG{FPE} = 'DEFAULT';
$SIG{HUP} = $SIG{ABRT} = $SIG{TERM} = $SIG{KILL} =  \&sig_handler;
$SIG{__WARN__} = $SIG{__DIE__} = sub { $logs->enqueue(shift) };

# now install all the other threads you want to run. 
# everything they have to do in case something goes wrong, 
# will be to simply warn() or die() - roughly told.
# hence the logger finction is quite simple:
sub logger {
   my $logfile = shift;
   open LOG, ">>$logfile" || die $!;
   while (my $msg = $logs->dequeue) {
      my $line = "[".localtime(time)."] $msg";
      chomp $line;
      print LOG "$line\n";
      flush LOG if $DEBUG;
   }
   close LOG;
}

[...]

sub sig_ignore {
   return unless @_;
   $logs->enqueue("Silently ignoring signal ".shift);
}

sub sig_pipe {
   return unless @_;
   my $warn = "Caught signal ".shift().", ";
   # append more information to the warning message
   # if necessary
   $logs->enqueue($warn);
}

# the sig_handler() function has to carefully wait for all 
# threads to terminate properly and then simply exit -
# which means again that there is only one process 
# to care for:
sub sig_handler {
   return unless @_;
   $logs->enqueue(undef);
   $logger->join;
   [...]
   exit 0;
}