c++ - Boost.Extension - simple inheritance sample - why we see no animals on linux? -

so try port boost.extension samples linux.

the sample described here. here code port (classes animals, animal prototype, main app, general all port idea described here, , some current linux progress here (some samples work needed!)). when compile sample under linux compiles, finds library animals outputs:

animals not found! 

which shall happen if(factories.empty()).

i try port extension samples onto crossplatform base - have tried same code under windows - works charm! finds animals , outputs:

creating animal using factory: cougar factory created animal: cougar age: 2 creating animal using factory: leopard factory created animal: leopard age: 3 creating animal using factory: puma factory created animal: puma age: 4 creating animal using factory: wildcat factory created animal: wildcat age: 5 

so... why behaves on linux same code? why works under windows?

update:

so how build stuff premake:

1. you svn here (only folder required)
2. you get premake platform or build source , put folder downloaded svn
3. you should have official boost compiled , installed (please read readme.txt file provide in directory) needed:
   • boost c++ library's (we tested version 1.4.16)
   • boost-extension ( use latest revision , adress part of boost 'boost/extension/**' we had make chandes (actually one) boost extension provide inside boost.extension.tutorial/libs/boost/extension/ folder when downloaded svn got it, header only )
   • boost-reflection ( use because of tutorial , use latest revision , adress part of boost 'boost/reflection/**' *and simplness recommend put boost.extension.tutorial/libs/boost/reflection * )
4. now when official boost in system, header boost-reflection , boost-extension in boost.extension.tutorial/libs/boost folder, premake4 executable inside boost.extension.tutorial/ folder can call boost.extension.tutorial/ premake4-build-windows.bat on windows sln visual studio or boost.extension.tutorial/ premake-build.sh makefiles.
5. you can find generated solution/makefiles inside generated projects folder.
6. have luck!=)

update 2:

project files for windows , linux in svn can aroung project creation premake - have boost, our svn, , reflection headers lib.

i debugged things on linux, news:

you running bullet no. 3 jeremy pack's post:

rtti not function expected across dll boundaries. check out type_info classes see how deal that.

i have tiny workaround patch (below) boost/extension/impl/typeinfo.hpp (but need talk maintainer of boost extension, really). not rely on builtin comparison rtti typeinfo's.

looking @ typeinfo.hpp, seems windows never uses typeinfo comparison, decided test 'strcmp' fallback method, , voila:

$ ld_library_path=. ./simple-inheritance  creating animal using factory: cougar factory created animal: cougar age: 2 creating animal using factory: leopard factory created animal: leopard age: 3 creating animal using factory: puma factory created animal: puma age: 4 creating animal using factory: wildcat factory created animal: wildcat age: 5 

---

in particular, can show type lookup convertible_ fails @ type_map.hpp, line 68;

• when conversion called extension dll itself, conversion happily finds match using rtti.
• however, when 'same' .get() done test application (across dll boundaries, i.e.) rtti different , no such match found, , line 74/75 hit:

.

73        if (it == instances_.end()) { 74          holder = new type_holder<storedtype>; 75          = instances_.insert(std::make_pair(t, holder)).first; 76        } 

patch

diff --git a/boost.extension.tutorial/libs/boost/extension/impl/typeinfo.hpp b/boost.extension.tutorial/libs/boost/extension/impl/typeinfo.hpp index 843fed2..09fc353 100644 --- a/boost.extension.tutorial/libs/boost/extension/impl/typeinfo.hpp +++ b/boost.extension.tutorial/libs/boost/extension/impl/typeinfo.hpp @@ -50,7 +50,7 @@ struct type_info_handler<default_type_info, classtype>   // list should expanded platforms  // compare type_info across shared library boundaries. -#if defined(__apple__) || defined(__gnuc__) || \ +#if defined(__apple__) || \      defined(boost_extension_force_fast_typeinfo)  namespace boost {  namespace extensions { @@ -90,7 +90,7 @@ inline bool operator>(const default_type_info& first,  }  // namespace extensions  }  // namespace boost  #else  // other os -#include <string> +#include <cstring>  namespace boost { namespace extensions {  inline bool operator<(const default_type_info& first,                 const default_type_info& second) {