my @email_list = ();
open(LIST,'<',"email_database.txt") or die "$!\n";

while(<LIST>){
   chomp $_;
   push(@email_list,$_);
}
close(LIST);

foreach my $address(@email_list){
   sendmail($address);
}

sub sendmail{
   my $address = $_[0];
   # what should I use here?
   if( mail was sent ) {return true}
}