BloombergLP::bdlc::CompactedArray_ConstIterator::operator-=

Decrement this iterator by the specified offset from the location referenced by this iterator, and return a reference providing modifiable access to this iterator. The returned iterator, it, referencing a CompactedArray array, remains valid as long as 0 <= it - array.begin() <= array.length(). The behavior is undefined unless CompactedArray_ConstIterator() != *this and 0 <= *this - array.begin() - offset <= array.length().