Description:
------------
---
From manual page: http://www.php.net/function.substr-replace
---

The description of the 'start' argument says:

"""
    If start is positive, the replacing will begin at the start'th offset into string.

    If start is negative, the replacing will begin at the start'th character from the end of string.
"""

This fails to account for the case where 'start' is zero.  Instead of "positive", it should say "non-negative", or "positive or zero", or "greater than or equal to zero".


Test script:
---------------
print substr_replace('bar', 'foo', 0);