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A cache is a kind of class member data that can very reasonably be
declared mutable. When the cache is changed, the physical state of the owning object changes, but its logical state, as seen by other objects, does not change. That's the kind of data that the mutable keyword is meant for. Kjell 2013-10-01 23:38, Dominique Würtz
skrev:
I'm implementing a custom Gtk::TreeModel for displaying database query results. In order to avoid storing the entire result in memory, I'm using a caching mechanism which stores only those rows in the neighborhood of recently queried rows. In my get_value_vfunc(), if a requested row is not in the cache, I need to update my cache. Unfortunately, the get_value_vfunc() is declared const and thus forbids mutating my TreeModel object which owns the cache. Any idea how to resolve this? Thanks! Dominique |