Attempts to remove the directory named by dirname.
The directory must be empty, and the relevant permissions must permit this.
Returns TRUE on success or FALSE on failure.
Note:
As of PHP 5.0.0 rmdir() can also be
used with some URL wrappers. Refer to Appendix M
for a listing of which wrappers support rmdir().
Note: When safe mode is enabled, PHP checks whether
the directory in which you are about to operate has the same UID (owner) as the
script that is being executed.