$fh = new ([params])
Constructor. Creates an IO::File object, passing any parameters to
the method open. If the open fails, the object is
destroyed. Otherwise, it is returned to the caller.
$fh = new_tmpfile
Constructor. Creates an IO::File object opened for read/write on a
newly created temporary file. If the system permits, the temporary
file is anonymous; if the temporary file cannot be created or opened,
the object is destroyed. Otherwise, it is returned to the caller.
$fh->open(filename[, mode[, perms]])
Opens the newly created filehandle. Accepts one, two, or three
parameters. With one parameter, it acts as a frontend for
Perl's built-in open function.
With two parameters, the first parameter is a filename, and the
second is the open mode, optionally followed by a third parameter,
the file permission value.