Finds the start of the next UTF-8 character in the string after @p.
@p does not have to be at the beginning of a UTF-8 character. No check
is made to see if the character found is actually valid other than
it starts with an appropriate byte.
If @end is %NULL, the return value will never be %NULL: if the end of the
string is reached, a pointer to the terminating nul byte is returned. If
@end is non-%NULL, the return value will be %NULL if the end of the string
is reached.
Finds the start of the next UTF-8 character in the string after @p.
@p does not have to be at the beginning of a UTF-8 character. No check is made to see if the character found is actually valid other than it starts with an appropriate byte.
If @end is %NULL, the return value will never be %NULL: if the end of the string is reached, a pointer to the terminating nul byte is returned. If @end is non-%NULL, the return value will be %NULL if the end of the string is reached.