How can I create a C++ function that generates a new random number each time it's called? [duplicate]

This question already has an answer here:

• Why do I get the same sequence for every run with std::random_device with mingw gcc4.8.1? 4 answers
• Random number generator repeats every time? 2 answers
• Random integers from a function always return the same number - why? 2 answers

Before you just flag it as duplicate, other questions weren't interested in a specific probability distribution

So, if I need to create a function that, let's say

vector<double> func(int input){
    random_device mch;
    default_random_engine generator(mch());
    vector<double> vec;
    for (int i = 0; i < input; i++){
        normal_distribution<double> distribution(0.0,2.0);
        vec.push_back(distribution(generator));
    }
    return vec;
}

I need to execute this function several times. If at first gives me, say, (5,2,89,20) vector, then no matter how many times I execute this function, I still get the same (5,2,89,20) vector How do I make it so it generates a random number each time?