Robert Ramey
This can't work.
load a pointer creates a new pointer with a copy of the original object.
adding the following to your test should make this clear
... std::cout << "ref: " << *m.ref << std::endl; ... std::cout << "ref: " << *m2.ref << std::endl;
Hmm, if I understand you correctly, then m2.ref should point to a copy of m.m[1] then, but not the same instance? The thing is, m2.ref isn't even that. Here's an enhanced example: I add a value variable to my dummy struct: struct dummy { int j; dummy() : j(-1) {} dummy(int i) : j(i) {} template<typename Archive> void serialize(Archive & ar, const unsigned int version) { ar & j; } }; And then print that value along with the addresses: ... std::cout << "0: " << &m.m[0] << " = " << m.m[0].j << std::endl; std::cout << "1: " << &m.m[1] << " = " << m.m[1].j << std::endl; std::cout << "2: " << &m.m[2] << " = " << m.m[2].j << std::endl; std::cout << "ref: " << m.ref << " = " << m.ref->j << std::endl; ... What I get is the following: 0: 0x8085c0c = 1 1: 0x8085c44 = 2 2: 0x8085c7c = 3 ref: 0x8085c44 = 2 0: 0x80864a4 = 1 1: 0x80864c4 = 2 2: 0x80864e4 = 3 ref: 0xbf81de0c = -1231556796 which indicates to me that it isn't a copy of the original element and that something unexpected is happening. As I understand Boost.Serialization's mechanics, one is allowed to store objects through pointers that are stored by-value elsewhere, as long as the by-value serialization is done before to the by-pointer one. I have some code where this (seemingly) works. For the above, e.g., replacing the map by a vector<dummy> makes everything work as expected: 0: 0x8082440 = 1 1: 0x8082444 = 2 2: 0x8082448 = 3 ref: 0x8082444 = 2 0: 0x8083368 = 1 1: 0x808336c = 2 2: 0x8083370 = 3 ref: 0x808336c = 2 Coincidince? Anyway, what would be the best way of doing this? Keeping pointers (instead of values) to dummy in the map should certainly fix the problem, right? Thanks! Bernhard