On 1/02/2018 15:38, Emil Dotchevski wrote:
My question still stands though. If you don't use exceptions, in C++, how do you protect users from calling member functions on objects that have not been initialized?
I mean haven't been initialized or failed to initialize.
The usual technique to manage that is to separate no-fail construction (constructor) from fail-possible initialisation (an init() method). Sometimes this requires weaker invariants than otherwise (eg. allowing an empty state). Often this two-phase construction is hidden from consumers by making both of them private and publishing a static factory method instead. Note this is also the same technique commonly employed by people who want to guarantee use of shared_ptr (for use with shared_from_this internally). The factory method technique also allows somewhat restoring a stronger invariant -- only the constructor and destructor need to cope with empty or otherwise uninitialised instances; other methods can be reasonably assured that no such instances escaped the factory method.