[boost] Re: Serialization - building shared libs

From: Robert Ramey (ramey_at_[hidden])
Date: 2004-10-18 20:28:11

This question would come up anytime the code is included in more than one
shared library (aka DLL).  Its not a serialization issue per se.  I would
think that for lots of reasons, code that implements a particular class
should be in only one DLL in general.  When using template generated code
this implies a certain amount of extra consideration on the part of the
programmer.  But I do believe that the best (and perhaps only reliable) way
to address this is to organize code modules so the problem is avoided.

I have been considering the issue of serialization code in DLLS but none of
the changes I would like to make address the situation you describe below.

Robert Ramey

"Neal Becker" <ndbecker2_at_[hidden]> wrote in message
news:cl1i9b$581$1_at_sea.gmane.org...
> I brought up the topic that int the current cvs serialization libs are
only
> built static, not shared.  The reason for this is that the library uses
> this construct:
> ,----[ /home/nbecker/stuff/A.hpp ]
> | // {{{ struct A
> |
> | struct A {
> |   int i;
> |   A() { i = 1; }
> |   static const A instance;
> | };
> |
> | // }}}
> |
> | extern const A A::instance = A();
> `----
>
> If this is included into 2 shared libraries, will A::instance be shared?
>
> I have tested this on Linux.  If you dlopen 2 different shared libs, it
will
> work correctly, if you set the flags RTLD_NOW|RTLD_GLOBAL.
>
> Since this will work correctly on some systems, I would like to see this
> supported.
>
> It is impossible to use serialization with boost::python without shared
> libs.
>
>
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