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
