Question

I am passing a vector pointer to another function which pushes data using that pointer:

void foo(vector<pair<int,int>> * vp){
 vp->push_back(pair<int,int>(1,1)); //causes segfault
}

void bar(vector<pair<int,int>> *vp = NULL){
  foo(vp);
}

The push_back causes segfault.

Answer 1

If it hurts, don’t do it. You should almost never pass things like vectors using pointers – use references instead:

void foo(vector<pair<int,int>> & vp){
 vp.push_back(pair<int,int>(1,1));
}