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c++booststlshared-ptrraii

Why use one vs the other: `boost::shared_array` VS `boost::shared_ptr<std::vector>`?

So to deal with large blobs of memory either for an image or similar there are clearly lots of options.

Since I'm a fan of smart pointers and RAII I'm wondering about whether it's smarter to go with :

  • a shared_ptr to a std::vector

or

  • to go with a shared_array pointing to a dynamically allocated array.

What are the conceptual, practical, and performance implications of choosing one vs the other?

Solution

  • It's the same as comparing std::vector vs. C array.

    Think about shared_array as a RAII C array. What you get is just automatic memory deallocation. Useful in cases when you deal with 3rd-party code that returns arrays. Theoretically it's faster than std::vector in some edge cases, but much less flexible and less secure.

    std::vector is probably the better choice.