Oops - I didn't see my post so I thought something had gone wrong and reposted. Apologies for the multiple posts.
On Jul 9, 11:57 am, Stodge <[EMAIL PROTECTED]> wrote: > Could it be a boundary problem? The static data is initialised by the > application. The problem arises when the python module tries to access > it. > > On Jul 5, 11:14 pm, Giuseppe Ottaviano <[EMAIL PROTECTED]> wrote: > > > > In Python, I retrive an Entity from the EntityList: > > > > elist = EntityList() > > > elist.append(Entity()) > > > elist.append(Entity()) > > > > entity = elist.get_at(0) > > > > entity.foo() > > > > But it crashes inside foo() as the private static data is empty; or > > > rather the string array is empty. I know before that point that the > > > private static data is valid when accessed earlier by the C++ code as > > > the program works fine. It just won't work from Python, so somehow the > > > private static data has been blown away but I can't work out where or > > > why. > > > Probably it is a problem of lifetime. What is the signature of append? > > Who deletes the appended Entity in C++ code? > > If append takes a raw pointer, Boost.Python copies the pointer but > > destroys the Entity object because it is a temporary and its reference > > count went to zero. So the pointer in the list is referring to a > > destroyed object, which results in undefined behaviour. > > > Did you have a look at the lifetime policies of Boost.Python? The > > simplest way to workaround the problem is using const reference > > arguments, and always use value semantics. If it can result in a > > performance penalty, another simple way is using shared_ptr's, which > > have their own reference count (different from the one in CPython > > lib), but Boost.Python does the magic to make them work together. > > > HTH, > > Giuseppe -- http://mail.python.org/mailman/listinfo/python-list
