Returns the type of the file. Possible values are fifo, char, dir, block, link, file, and unknown.
Returns FALSE if an error occurs. filetype() will also produce an E_NOTICE message if the stat call fails or if the file type is unknown.
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提示: As of PHP 5.0.0 this function can also be used with some URL wrappers. Refer to 附錄 M for a listing of which wrappers support stat() family of functionality.
See also is_dir(), is_file(), is_link(), file_exists(), stat(), and mime_content_type().