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Is there any benefit to using new?
I've heard that in modern C++, smart pointers are preferred to raw pointers for ownership (the so-called RAII principle, as I understand it).
This makes sense, and since then I've always used them throughout my projects. This makes me realize though, that I can't really remember the last time I've used new to allocate anything and have started to wonder if it's actually useful anymore.
In what (if any) situations are there benefits in using new to allocate memory over std::make_unique or std::make_shared?
1 answer
Well, you still need (placement) new for the implementation of the smart pointers themselves.
You would also use it (or malloc) to implement custom allocators, for example: https://www.boost.org/doc/libs/1_78_0/libs/pool/doc/html/boost/default_user_allocator_new_delete.html.
One unusual scenario is the following: Just recently I was involved in the implementation of a component that had a special requirement, namely that some of its objects should have "infinite" life time. These objects should therefore also not be destroyed at the end of main, but exist up to the point of actual process termination. Therefore, what was needed there was a new without delete.
Maybe others have more examples - at least I can confirm your view that the use of new has almost completely disappeared from source code.
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