Question

For example:

boost::shared_ptr<int> test() {
    boost::shared_ptr<int> x(new int(3));
    return x;
}

void function() {
    int y = *test();
    ...
}

Is it also a bad idea to use shared_ptr to avoid copying the whole object? Like a vector of matrices/images for example.

Answer 1

In the general case, no. Your example copies the contents of the shared_ptr, and then the original value is deleted.

Now, the bigger issue here is that it’s fantastically inefficient to do a dynamic memory allocation for an int, but I’m assuming you’re not doing that in real code. 🙂