[Boost-users] Antwort: boost::any, type_info, and dynamically loaded libraries

From: bernhard.maeder_at_[hidden]
Date: 2006-10-18 02:29:35

boost-users-bounces_at_[hidden] schrieb am 17.10.2006 18:18:36:

>
> I've instrumented the any_cast code and have verified that the
> type_info.name() strings for both the stored and requested types are
> the same. However, the operator== for the type_info's is still
> returning false.
>

I'm not sure if that's quite the same problem, but I had similar symptoms
with two python extension modules (which are shared libraries, too). The
point was that the type_info seemed to be the same, i.e. type_info.name(),
but there still were two different instances around. Unfortunately, the
compiler does not compare the type_info.name() but the addresses of the
instances.

See:

http://wiki.python.org/moin/boost.python/CrossExtensionModuleDependencies

The solution was to link the shared libraries with vague linkage enabled:

http://gcc.gnu.org/onlinedocs/gcc/Vague-Linkage.html

HTH
Bernhard
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