[boost] [serialization][1.35.0] incompatible change in guid_initalizer?

From: Bernd Speiser (bernd.speiser_at_[hidden])
Date: 2008-03-26 11:41:33

Hi,

using the serialization library in various versions, I encounter a 
problem with exporting guids when changing from boost 1.34.1 to 1.35.0
I am currently using gcc 4.3.0 (recent stable release) under openSuSE 10.2.

I am separating the exporting macros into a header xxx_export.h. This is 
done to avoid excessive compilation times for files in which the export 
code is not needed. Moreover, various classes which have export code are 
separated into several files. Thus, I need to #include more than one 
xxx_export.h header into the final program cpp file.

I get the follwing error during compile:

header2_export.h:9: error: conflicting declaration ‘const 
boost::archive::detail::guid_initializer<Derived2>& 
<unnamed>::boost_serialization_guid_initializer_9’
header1_export.h:9: error: 
‘<unnamed>::boost_serialization_guid_initializer_9’ has a previous 
declaration as ‘const 
boost::archive::detail::guid_initializer<Derived1>& 
<unnamed>::boost_serialization_guid_initializer_9’

Obviously, the symbol names are derived from the line number in the 
header file, right? Using two (or more) different export header files, 
this leads to confusion.

I tried to remedy the situation by enclosing the
BOOST_CLASS_EXPORT_GUID ()
macros in the two export header files in two different namespaces.
OK, that worked.

HOWEVER - it is not backward compatible with boost version 1.34.1. If I 
use the code that works with 1.3.50 with the earlier version, I get:

In file included from exportTestn.cpp:10:
header1n_export.h:10: error: expected initializer before ‘<’ token
header1n_export.h:10: error: ISO C++ forbids declaration of ‘type name’ 
with no type
header1n_export.h:10: error: wrong number of template arguments (1, 
should be 2)
/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.3.0/../../../../include/c++/4.3.0/bits/stl_pair.h:72: 
error: provided for ‘template<class _T1, class _T2> struct std::pair’
header1n_export.h:10: error: explicit instantiation of non-template ‘int 
derived1::boost::archive::detail::export_archives_invoke’
header1n_export.h:10: error: expected `;' before ‘<’ token
In file included from exportTestn.cpp:12:
header2n_export.h:10: error: expected initializer before ‘<’ token
header2n_export.h:10: error: ISO C++ forbids declaration of ‘type name’ 
with no type
header2n_export.h:10: error: wrong number of template arguments (1, 
should be 2)
/usr/local/lib/gcc/x86_64-unknown-linux-gnu/4.3.0/../../../../include/c++/4.3.0/bits/stl_pair.h:72: 
error: provided for ‘template<class _T1, class _T2> struct std::pair’
header2n_export.h:10: error: explicit instantiation of non-template ‘int 
derived2::boost::archive::detail::export_archives_invoke’
header2n_export.h:10: error: expected `;' before ‘<’ token

Am I doing something wrong here?
Is there a solution which works for both boost::serialization versions?

I have attached the relevant files for reference. Note that files 
header1.h, header2.h, header1_export.h and header2_export.h are without 
the additional namespace, while files header1n.h, header2n.h, 
header1n_export.h, and header2n_export.h are WITH the additional namespace.

Thanks for any help.

Bernd