[container.requirements]
Change: Complexity of size() member functions now constant
Rationale: Lack of specification of complexity of size() resulted in
divergent implementations with inconsistent performance characteristics.
Effect on original feature:
Some container implementations that conform to C++ 2003 may not conform to the
specified size() requirements in this International Standard. Adjusting
containers such as std::list to the stricter requirements may require
incompatible changes.
[container.requirements]
Change: Requirements change: relaxation
Rationale: Clarification.
Effect on original feature:
Valid C++ 2003 code that attempts to meet the specified container requirements
may now be over-specified. Code that attempted to be portable across containers
may need to be adjusted as follows:
not all containers provide size(); use empty() instead of size() == 0;
not all containers are empty after construction (array);
not all containers have constant complexity for swap() (array).
[container.requirements]
Change: Requirements change: default constructible
Rationale: Clarification of container requirements.
Effect on original feature:
Valid C++ 2003 code that attempts to explicitly instantiate a container using
a user-defined type with no default constructor may fail to compile.
[sequence.reqmts], [associative.reqmts]
Change: Signature changes: from void return types
Rationale: Old signature threw away useful information that may be expensive
to recalculate.
Effect on original feature:
The following member functions have changed:
erase(iter) for set, multiset, map, multimap
erase(begin, end) for set, multiset, map, multimap
insert(pos, num, val) for vector, deque, list, forward_list
insert(pos, beg, end) for vector, deque, list, forward_list
Valid C++ 2003 code that relies on these functions returning void (e.g., code that creates a pointer to member function that points to one of these functions) will fail to compile with this International Standard.
[sequence.reqmts], [associative.reqmts]
Change: Signature changes: from iterator to const_iterator
parameters
Rationale: Overspecification.
Effects:
The signatures of the following member functions changed from taking an
iterator to taking a const_iterator:
insert(iter, val) for vector, deque, list, set, multiset, map, multimap
insert(pos, beg, end) for vector, deque, list, forward_list
erase(iter) for set, multiset, map, multimap
erase(begin, end) for set, multiset, map, multimap
all forms of list::splice
all forms of list::merge
Valid C++ 2003 code that uses these functions may fail to compile with this International Standard.
[sequence.reqmts], [associative.reqmts]
Change: Signature changes: resize
Rationale: Performance, compatibility with move semantics.
Effect on original feature:
For vector, deque, and list
the fill value passed to resize is now passed by reference instead of
by value, and an additional overload of resize has been added. Valid
C++ 2003 code that uses this function may fail to compile with this International
Standard.