Returns the time the file was last changed, or FALSE in case of an error. The time is returned as a Unix timestamp.
Note: In most Unix filesystems, a file is considered changed when its inode data is changed; that is, when the permissions, owner, group, or other metadata from the inode is updated. See also filemtime() (which is what you want to use when you want to create "Last Modified" footers on web pages) and fileatime().
Note also that in some Unix texts the ctime of a file is referred to as being the creation time of the file. This is wrong. There is no creation time for Unix files in most Unix filesystems.
Note: The results of this function are cached. See clearstatcache() for more details.
See also filemtime()