17 Library introduction [library]

17.3 Definitions [definitions]

17.3.27 valid but unspecified state [defns.valid]

an object state that is not specified except that the object's invariants are met and operations on the object behave as specified for its type
Example: If an object x of type std::vector<int> is in a valid but unspecified state, x.empty() can be called unconditionally, and x.front() can be called only if x.empty() returns false.  — end example ]