std::unique_ptr looks like a good option. then again if the typical usage is like so:
cachePtr = CacheFactory::createCacheFactory(pp)->create(); it seems simple enough to just return the bare object EB On Wed, Sep 6, 2017 at 1:27 PM, David Kimura <dkim...@pivotal.io> wrote: > What type should C++ object creation functions return (e.g. pointer, smart > pointer, reference, etc.)? Several of our C++ API's return shared > pointers. For example in the following function signature [1]: > > std::shared_ptr<CacheFactory> CacheFactory::createCacheFactory(...); > > Here the only case I can see for shared pointer is to indicate ownership of > CacheFactory. Ideally this should probably be std::unique_ptr because > callee shouldn't share ownership. However, I don't see the point of using > a pointer at all.. I suggest we return the bare object, like the following > signature: > > CacheFactory CacheFactory::createCacheFactory(...); > > In C++03, this would have been a performance hit because we'd end up with > an added call to the copy constructor. In C++11, std::unique_ptr gives > std::move for free and thus avoids copy-constructor call. However, most > modern C++11 compilers already perform copy-elision here. In fact, C++17 > standard dictates that compilers must perform RVO here. Therefore it > doesn't seem to me that std::shared_ptr or std::unique_ptr buys us much in > this situation. > > Thoughts? > > Thanks, > David > > > [1] https://github.com/apache/geode-native/blob/develop/ > cppcache/include/geode/CacheFactory.hpp#L54 >
