chown
It should be noted that a call to any of those functions will cache all of the file's information, not just the information that is returned.
Obviously it is clear that the following requires you to clear the cache.
<?php
$size1 = filesize($filename);
unlink($filename);
$size2 = filesize($filename);
// $size2 still equals $size1, unless you cleared the stat cache in between.
?>
<?php
$access = fileatime($filename);
unlink($filename);
$size = filesize($filename);
// $size will be the filesize before it was unlinked, because the filesize was cached when fileatime was called, even though the two functions wouldn't appear to have anything to do with either other.
?>
Confirmed on a windows system.
clearstatcache
(PHP 4, PHP 5)
clearstatcache — Clears file status cache
Description
void clearstatcache
( void
)
When you use stat(), lstat(), or any of the other functions listed in the affected functions list (below), PHP caches the information those functions return in order to provide faster performance. However, in certain cases, you may want to clear the cached information. For instance, if the same file is being checked multiple times within a single script, and that file is in danger of being removed or changed during that script's operation, you may elect to clear the status cache. In these cases, you can use the clearstatcache() function to clear the information that PHP caches about a file.
You should also note that PHP doesn't cache information about non-existent files. So, if you call file_exists() on a file that doesn't exist, it will return FALSE until you create the file. If you create the file, it will return TRUE even if you then delete the file. However unlink() clears the cache automatically.
Note: This function caches information about specific filenames, so you only need to call clearstatcache() if you are performing multiple operations on the same filename and require the information about that particular file to not be cached.
Affected functions include stat(), lstat(), file_exists(), is_writable(), is_readable(), is_executable(), is_file(), is_dir(), is_link(), filectime(), fileatime(), filemtime(), fileinode(), filegroup(), fileowner(), filesize(), filetype(), and fileperms().
Return Values
No value is returned.
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User Contributed Notesclearstatcache
stangelanda at gmail dot com
24-Jan-2008 09:35
24-Jan-2008 09:35