+1 for the overall idea ! On Fri, Jul 18, 2014 at 10:17 PM, Ralph Castain <r...@open-mpi.org> wrote: > > * add an OBJ_CLASS_DEREGISTER and require that all instantiations be > matched by deregister at close of the framework/component that instanced > it. Of course, that requires that we protect the class system against > someone releasing/deconstructing an object after the class was deregistered > since we don't know who might be using that class outside of where it was > created. > > my understanding is that in theory, we already have an issue and fortunatly, we do not hit it : let's consider a framework/component that instanciate a class (OBJ_CLASS_INSTANCE) *with a destructor*, allocate an object of this class (OBJ_NEW) and expects "someone else" will free it (OBJ_RELEASE) if this framework/component ends up in a dynamic library that is dlclose'd when the framework/component is no more used, then OBJ_RELEASE will try to call the destructor which is no more accessible (since the lib was dlclose'd)
i could not experience such a scenario yet, and of course, this does not mean there is no problem. i experienced a "kind of" similar situation described in http://www.open-mpi.org/community/lists/devel/2014/06/14937.php back to OBJ_CLASS_DEREGISTER, what about an OBJ_CLASS_REGISTER in order to make this symmetric and easier to debug ? currently, OBJ_CLASS_REGISTER is "implied" the first time an object of a given class is allocated. from opal_obj_new : if (0 == cls->cls_initialized) opal_class_initialize(cls); that could be replaced by an error if 0 == cls->cls_initialized and OBJ_CLASS_REGISTER would simply call opal_class_initialize of course, this change could be implemented only when compiled with OPAL_ENABLE_DEBUG Cheers, Gilles
