Re: [Cppcms-users] Plugins and templates

[Artyom <art...@ya...>]

> 
> The problem is, this  doesn't work either, still getting std::bad_cast
> exceptions. It works only if  you cast the shared_ptr to
> content::hello_plugin by dynamic_pointer_cast  before passing it to
> render(). And that's the point - the dispatcher does not  know which
> class to cast to.
> 

Before we continue lets see following:

Is following happens (I think now I undestand what happens)?

  You load plugin foo - say libfoo.so
  You load skin libfoo_view.so that uses class that created in libfoo.so ?
  You compile a cppcms application bar with -rdynamic and it fails.

Am I right?

If so, what happens is following. libfoo is loaded and libfoo_view.so is loaded
but each one of them do not see symbols one of other.

If so you need to do one of following:

1. Make sure libfoo.so loads first before libfoo_view.so (i.e. before creating 
service instance)
2. When you load libfoo.so you need to dlopen it with RTLD_GLOBAL flag so 
libfoo_view.so
   will see it symbols.
3. Then load libfoo_view.so. So this probably should be


You may also make sure that libfoo_view.so loads with RTLD_GLOBAL but for this 
you need
to change a little the code in CppCMS: src/views_pool.cpp 

And change the line:
   handler_ = dlopen(file_name.c_str(),RTLD_LAZY);
to 
   handler_ = dlopen(file_name.c_str(),RTLD_LAZY | RTLD_GLOBAL);


And laso dlopen your plugins with this flag. Then all symbols will be visible to
pluging and views and casing would work.

Simplest way to check if this helps: before you alter the code just write in 

   int main(int argv,char **argc)
   { 
      void *h = dlopen("/path/to/plugin.so",RTLD_LAZY | RTLD_GLOBAL);
   }

If this helps then these changes I'm talking would help and I'll update CppCMS
to load libraries with this flag.


Artyom

-