I would recommend tracing with the debugger trough serialization of
optional<string> in portable binary archive to see how it's different
from serialization in binary or text archive.
I've performed a bit more analysis and it looks like serialization of
optional<> with any non-trivial types is broken in 1.64.
The serialization/optional.hpp load function:
template
void load(
Archive & ar,
boost::optional< T > & t,
const unsigned int /*version*/
)[...]
In 1.63, constructed space for the type with:
detail::stack_construct aux(ar, item_version);
ar >> boost::serialization::make_nvp("value", aux.reference());
t.reset(aux.reference());
which ensures the constructor is called. However, for 1.64 this changed to:
detail::stack_allocate<T> tp; // <<<<<<<<<<<<<<
ar >> boost::serialization::make_nvp("value", tp.reference());
t.reset(boost::move(tp.reference()));
ar.reset_object_address(
t.get_ptr(),
& tp.reference()
);
Unfortunately, this only allocates (zero'd) space for the object, and some
objects (in this case, std::string in g++ 4.6) are not valid as such.
I see that in 1.65 this changed again, to the simpler:
if(! t.is_initialized())
t = T();
ar >> boost::serialization::make_nvp("value", *t);
It seems I was just unlucky to choose 1.64. I've moved to 1.66 and it's all
working.
--
Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html
