Function type declaration for UCharIterator.move().
Use iter->move(iter, index, UITER_ZERO) like CharacterIterator::setIndex(index).
Moves the current position relative to the start or limit of the iteration range, or relative to the current position itself. The movement is expressed in numbers of code units forward or backward by specifying a positive or negative delta. Out of bounds movement will be pinned to the start or limit.
This function may perform slowly for moving relative to UITER_LENGTH because an iterator implementation may have to count the rest of the UChars if the native storage is not UTF-16.
When moving relative to the limit or length, or relative to the current position after setState() was called, move() may return UITER_UNKNOWN_INDEX (-2) to avoid an inefficient determination of the actual UTF-16 index. The actual index can be determined with getIndex(UITER_CURRENT) which will count the UChars if necessary. See UITER_UNKNOWN_INDEX for details.