Returns TRUE if the file or directory specified by filename exists; FALSE otherwise.
On windows, use //computername/share/filename or \\computername\share\filename to check files on network shares.
Note: The results of this function are cached. See clearstatcache() for more details.
Tip: As of PHP 5.0.0 this function can also be used with some URL wrappers. Refer to Appendix L for a listing of which wrappers support stat() family of functionality.
See also is_readable(), is_writable(), is_file() and file().