no no, that's exactly my point!
thanks for the details and the dicussion, I will investigate the possible benefits with a little more detail.
Actually I was looking to (possibly) optimize the usage of some matrix_44 objects which get copied around a little too much, but after your description I'm not even sure if it's data is dynamically allocated or not! Tomorrow I will check it and if it's allocated on the heap the move constructor may bring some optimizations
Actually, as you pointed, my rule of thumb is that if data pointers can be swapped I implement move constructors, else I stick with copies!