Description:
------------
the actual behavior of the offset for strrpos is exactly the opposite of what the docs lead me to expect.




Reproduce code:
---------------
---
From manual page: function.strrpos#Description
---

Note:  As of PHP 5.0.0 offset  may be specified to begin searching an arbitrary number of characters into the string. Negative values will stop searching at an arbitrary point prior to the end of the string.  

==================

but what actually happens is that 

Positive values define the stopping point 
and 
Negative values define the starting point.



Expected result:
----------------
$foo = "0123456789a123456789b123456789c";

echo strrpos($foo, '7', -5);  //claim: stop searching after n chars (from the end of the string)

//Expected:  27  || Actual: 17

//==============
echo strrpos($foo, '7', 20);  //claim: start searching (backwards) n chars into the string.

//Expected:  17  || Actual: 27

//==============
echo strrpos($foo, '7', 28);

//Expected:  27  || Actual: false



Actual result:
--------------
as you can see from the examples, negative numbers define the point where it *starts* searching backwards offset from the end of the string.

and positive numbers define the point from the beginning of the string where it *stops* searching.