###

# Serialization

## Release Notes

Requirements
Differences from version 1.37
Differences from version 1.37
Differences from version 1.35
Differences from version 1.34
Differences from version 1.33
Differences from version 1.32
Pending Issues

As of this is written, there are no known bugs. However, due to compiler/library quirks and or bugs, some tests fail with some combinations of compilers and libraries.

## Requirements

This library has been tested against Boost version 1.39 and 1.40.

Changes have been made to archive classes included with the library. Users who have used these a guide to making their own archive classes will find that these will likely no longer compile. This can be remedied by making the following changes in the code which instantiates these archive classes.

Old Code:
``

        ...
        #include <boost/archive/impl/archive_pointer_iserializer.ipp>
        ...
        template class detail::archive_pointer_iserializer<naked_text_iarchive> ;
        ...
        template class detail::archive_pointer_iserializer<text_iarchive> ;

should be replaced with this new code:

``

        #include <boost/archive/impl/archive_serializer_map.ipp>
        ...
        template class detail::archive_serializer_map<naked_text_iarchive> ;
        ...
        template class detail::archive_serializer_map<text_iarchive> ;

## Differences from Boost 1.39

- It is now possible to serialize an object through a pointer to a class which implements its own `new/delete` operators. This functionaly is not available on some compilers.
- serialization of polymorphic objects has been sped up considerably.

As of this writing, all bug reports filed as TRAK tickets have been addressed. There are some TRAK tickets pending which would best be described as feature requests. See Pending Issues.

## Differences from Boost 1.37

There are no new features in this version. As of this writing, all bug reports filed as TRAK tickets have been addressed. There are some TRAK tickets pending which would best be described as feature requests. See Pending Issues.

## Differences from Boost 1.36

There are no new features in this version. As of this writing, all bug reports filed as TRAK tickets have been addressed.

## Differences from Boost 1.35

- The library is now thread safe. That is, multiple archives can be open in different threads. This has been implmented with a lock-free algorithm to avoid any performance bottlenecks.
- Serialization of types defined in shared libraries is now supported. shared libraries (DLLS) can be loaded/unloaded dynamically at runtime. This includes the serialization of instances of abstract base classes so that a program can be written so as to be compatible with as yet undefined and un-implemented code.
- The extended type info system has been enhanced to in order to implement the above. It is now a general purpose system for creating and casting of types about which is only known a string ID and an abstract base class.
- All bug reports filed as TRAK tickets have been addressed.
- As of this writing, the library will fail build on older compilers such as MSVC before version 7.1 and older versions of Borland compilers. This might or might not change in the future.

## Differences from Boost 1.34

- Enhanced support for fast serialization for native binary archives. By Mattias Troyer.
- Improved implementation of "export" functionality. Removes header ordering requirement and eliminates the maintenance of a pre-determined list of "known archives" By David Abrahams.
- Improved support for STLPort.

## Differences from Boost 1.33

- Native Binary archives use the `std::streambuf` interface. This should result in noticeably faster execution in many cases.

## Differences from Boost 1.32

- Dynamic Linking Library (DLLs and shared libraries) for platforms which support them. See Automatic Linking on Windows.
- Implementation of auto-link for compilers which can support this.
- Better support for Argument Dependent Lookup and two-phase lookup. This results in simpler rules regarding the placing of serialization specializations namespaces.
- Enhanced documentation to help explain usage of the above.
- Adjustments to improve support for less conformant compilers.
- Improved `const` correctness for save/load operators. Note that this may produce compile time errors in code which compiled without problem in earlier boost releases. In most cases the fix is trivial. In other cases, code should be scrutinized to be sure that it doesn't use the serialization system in a way which may introduce subtle bugs in to the program. A fuller explanation of this issue can be found here.
- A new implementation of serialization for `shared_ptr<T>`. This is compatible with public interface of `shared_ptr<T>` so it should be more robust and not have to change in the future. The implementation optionally includes code to load `shared_ptr<T>` stored in archives created with boost 1.32. This code is stored in 'he header: `boost/serialization/shared_ptr_132.hpp`. If your application needs to load archives created with boost 1.32 libraries, include the above header before each inclusion of `boost/serialization/shared_ptr.hpp`.
- More compilers tested and supported.
- Miscellaneous bug fixes.

## Pending issues

- Rvalues cannot be serialized. It would be possible to implement this for untracked types, but this has not been done.
- Pointers to pointers cannot currently be serialized
- Its possible that `std::string` and `std::wstring` contain characters such as '\0' and -1 (EOF) which cannot be rendered in text and XML archives without an escape mechanism. Currently there is no such escape mechanism implemented.
- A subtle error in the implementation of serializaton of `std::map` is fixed in this version. Unfortunately, the fix breaks serialization of `std::map` for those compilers which do not support partial template specialization. Also, types which contain pointers or tracked types might not work correctly.

Aside from the above, there are a number of issues related to specific platforms. These are listed in Specific Compiler/Library Issues.

© Copyright Robert Ramey 2002-2009. Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)