Returns the numeric position of the last occurrence of needle in the haystack string. Note that the needle in this case can only be a single character. If a string is passed as the needle, then only the first character of that string will be used.
If needle is not found, returns FALSE.
Megjegyzés: It is easy to mistake the return values for "character found at position 0" and "character not found". Here's how to detect the difference:
If needle is not a string, it is converted to an integer and applied as the ordinal value of a character.