Returns the numeric position of the first occurrence of needle in haystack.
The optional offset parameter specifies the position from which the search should be performed.
If needle is not found,
iconv_strpos() 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_strpos() 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.
If charset parameter is omitted, string are assumed to be encoded in iconv.internal_charset.