#!/usr/bin/perl -w

BEGIN {
  open(STDERR, ">>foo.err") or die "invisible error";
  warn localtime() . ": $0 started " . $/;
}

use strict;
use Foo;

start();                     # start the program

while (1) {
  process();               # the main program logic 
  goto_sleep();          # goto sleep
}

### and then, in Foo.pm #######
sub process {

  # create an IMAP connection
  eval {
    $imap = Mail::IMAPClient->new(  
      Server    => $IMAP,
      User      => $UNAME,
      Password  => $PWD, 
      Uid       => 0, 
      Debug     => $DEBUGGING,
    ) or carp "Cannot connect to $IMAP as $UNAME: $@";
  };

  open  LOG, ">>foo.log";
  print LOG ($@) ? "failed with $@\n" : "connected successfully\n";
  close LOG;
}