use IO::Handle;

my $fh = IO::Handle->new();
if ($fh->fdopen("dump.dat", "w")) {
  $fh->autoflush(1);
  $fh->print($mystuff);
  # ... blah blah blah
  $fh->close() or
    die("Unable to close file: $!\n");
}
else {
  die("Unable to open file: $!\n");
}