[TYPO3-english] SYS_LASTCHANGED vs. tstamp

[Victor Livakovsky]

Hi, Marco.

> So what is the difference between SYS_LASTCHANGED and tstamp. When will 
> those fields update?

I also was interesting in this and found a method in class.tslib_content.php 
called: function lastChanged($tstamp).
Here are lines from it's description:
* Sets the SYS_LASTCHANGED timestamp if input timestamp is larger than 
current value.
* The SYS_LASTCHANGED timestamp can be used by various caching/indexing 
applications to determine if the page has new content.
* Therefore you should call this function with the last-changed timestamp of 
any element you display.

So, as you see, SYS_LASTCHANGED is used for caching/indexing and should be 
changed by extensions (however, I've never seen, that people are using 
it...), and tstamp, I guess, should be changed by core, when you, f.e., 
change page properties or make some changes of content on a page.