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Maybe you should actually read what references are and what they do.

You can pass by reference.


void foo(std::vector<T>& myvector)
{
myvector.push_back(/*blah*/);
}

std::vector<T> myvec;
foo(myvec);

I don't understand what you are trying to point out.
It's up to your function whether or not it will modify the data passed as arguments or not. Pass a const reference if you don't want it to modify...

Your function takes vectors. Why are you trying to pass pointer to pointers to elements to it?