Returns the numeric position of the last occurrence of needle in haystack.
If needle is not found,
iconv_strrpos() will return
If haystack or needle is not a string, it is converted to a string and applied as the ordinal value of a character.
In contrast to strpos(), the return value of iconv_strrpos() is the number of characters that appear before the needle, rather than the offset in bytes to the position where the needle has been found. The characters are counted on the basis of the specified character set charset.