Passing containers of pointers to const as arguments

Question

I have quite a few functions that take containers of pointers to const objects as arguments. I need to call these functions with containers of pointers to non-const objects. I seem to remember reading somewhere that this is not allowed. Is there a way to work around this other than writing 2 copies of the function?

Example(this code doesn't compile):

#include <vector>
#include <iostream>
using namespace std;

void fn(vector<const int *> par) {
    cout<<"Function with const ptrs\n"<<endl;
}

int main()
{
    vector<int *>v;
    fn(v);
}

Answer 1

You could initialise a new vector.

#include <vector>
#include <iostream>
using namespace std;

void fn(vector<const int *> par) {
    cout << "Function with const ptrs\n" << endl;
}

int main()
{
    vector<int *>v;
    fn(vector<const int *>(v.begin(), v.end()));
}

Answer 2

If it is an option, consider making your functions take ranges, for example something like:

template<typename t_iterator>
void fn(t_iterator beg_iter, t_iterator end_iter) {
    for(; beg_iter != end_iter; ++beg_iter) {
        // do something
    }
}

This should operate over vector<int*> and vector<const int*> and also deque<int*> etc