Returns the size of the file in bytes, or FALSE in case of an error.
Note:
Because PHP's integer type is signed and many platforms use 32bit integers,
filesize() may return unexpected results for files which
are larger than 2GB. For files between 2GB and 4GB in size this can usually
be overcome by using sprintf("%u", filesize($file)).
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 J for a listing of which wrappers support
stat() family of functionality.