Re: [Boost-users] [serialization] Export question

Subject: Re: [Boost-users] [serialization] Export question
From: Robert Ramey (ramey_at_[hidden])
Date: 2009-04-08 13:19:49

"Tom Aylesworth" <taylesworth_at_[hidden]> wrote in message 
news:0D75E0E38A78ED40B5933CCBB98119F3900F5CDABF_at_hermes.realitymobile.local...
I just want to make sure that I understand the use of the Serialization 
library's EXPORT macros.  On the "Serializable Concepts" page of the 
documentation, it states:

--
The macro BOOST_CLASS_EXPORT_GUID associates a string literal with a 
class. . This permits each class to be in a separate header file along with 
its string identifier.
*** Hmmm - my current copy of the documentation doesn't include the above 
statement.  It shouldn't be there now.  I'll double check.
However, on the "Special Considerations" page, I find:
--
Note that the implementation of this functionality requires that the 
BOOST_CLASS_EXPORT macro appear after and the inclusion of any archive class 
headers for which code is to be instantiated. . Note that including 
BOOST_CLASS_EXPORT in the "a.hpp" header itself as one would do with other 
serialization traits will make it difficult or impossible to follow the rule 
above regarding inclusion of archive headers before BOOST_CLASS_EXPORT is 
invoked. This is different than other serialization traits which would 
normally be included in same file as the class declaration.
--
***** The above is correct.
The associated example shows the EXPORT macro following the #include of the 
header defining the class to be exported.
**** hmmm - which example?
I would certainly much rather have the EXPORT macros appear in the header 
with the class that defines them.  I take it that means I have to guarantee 
that the file actually responsible for operating on an archive includes my 
headers with the class definitions and EXPORT macros *after* including the 
appropriate archive headers (e.g., "boost/archive/xml_oarchive.hpp").
Is that correct?  Are there any other gotchas I should be aware of if I 
place the EXPORT macros in the headers with the classes to be exported?
****
my advice:
a) Don't put EXPORT macro in headers.
b) Add a small module to your main code which looks like
#include archive
.... // repeat as necessary
#include "a.hpp"
BOOST_CLASS_EXPORT(A)
.... // repeat as necessary for each class defined in the main line
c) for each DLL - do the same thing for classes defined in the DLL.
Robert Ramey
Thanks,
Thomas Aylesworth
Senior Software Engineer
Reality Mobile
_______________________________________________
Boost-users mailing list
Boost-users_at_[hidden]
http://lists.boost.org/mailman/listinfo.cgi/boost-users