[Rcpp-devel] Life-cycle of Rcpp::XPtr

The copy constructor doesn't actually create a copy, it only acts as a wrapper that preserves the same EXTPTR object, it is akin to increasing the reference count, so the C++ class wrapped in the EXTPTR is only released when the EXTPTR can be garbage-collected, i.e. all references are gone (including all "copies").
[Of course that is not true if you were to create two XPtrs with the same pointer and a finalizer each, but that would be a bad idea, obviously].