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…the constructor The callback list of each prototype was created on the first use with double checked locking, but the first check read the std::shared_ptr without the lock while another thread could be assigning it under the lock. std::shared_ptr is not atomic, so that's a data race (ThreadSanitizer reports it when several threads use a fresh HeterCallbackList or HeterEventDispatcher at the same time). Now all the lists are created in the constructor (the count of prototypes is a compile time constant, usually a few), so looking up a list needs no lock at all. A moved-from object gets new empty lists so it's still usable, as before. callbackListListMutex is kept for the operations that modify the array (copy, move, swap). Added unit tests.
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The callback list of each prototype was created on the first use with double checked locking, but the first check read the std::shared_ptr without the lock while another thread could be assigning it under the lock. std::shared_ptr is not atomic, so that's a data race (ThreadSanitizer reports it when several threads use a fresh HeterCallbackList or HeterEventDispatcher at the same time).
Now all the lists are created in the constructor (the count of prototypes is a compile time constant, usually a few), so looking up a list needs no lock at all. A moved-from object gets new empty lists so it's still usable, as before. callbackListListMutex is kept for the operations that modify the array (copy, move, swap).
Added unit tests.