UE4 uses their own C++ containers (such as TArray and TMap), which is very far from modern C++ (which recommends using STL like a part of the language). And UE4

UE4 uses their own C++ containers (such as TArray and TMap), which is very far from modern C++ (which recommends using STL like a part of the language). And UE4's macro system has garbage collection support built in, which would upset the modern C++ folks using shared_ptr and unique_ptr. They don't even like macros, they prefer using template metaprogramming whenever possible...