This is a versioning bug. The first of the following two lines is missing from the example shipped with 1.40:<div><br></div><div><div>BOOST_CLASS_VERSION(bus_schedule::trip_info, 2) // missing from example</div><div>// BOOST_CLASS_VERSION(bus_schedule, 2)  // not necessary for example to work.</div>
<div><br></div><div>When the schedule is recreated, the driver is not copied to the bus_schedule as the field is contained in the nested struct. </div><div><br></div><div>When I replace the second macro with the first one, the example works.</div>
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