Returns TRUE if the file specified by filename exists; FALSE otherwise.
This function will not work on remote files; the file to be examined must be accessible via the server's filesystem.
The results of this function are cached. See clearstatcache() for more details.
Using Windows shares: On windows, use //computername/share/filename or \\\\computername\share\filename to check files on network shares.
See also is_readable(), is_writable(), is_file() and file().