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.