Can I return Null iterator from a function

问题

I'm porting some old code from vs6.0 to vs2015.

A function is returning a Null iterator; the caller compares it with NULL, which works in vs6.0, but in vs2015 that's an error. Is it possible that we can return a null iterator?

The old code looks something like this:

vector<string*>::iterator FindByCode()
{
   //some code
   if (itr == str.end) {
       return NULL;
   } else {
       return itr;
   }
}

int main()
{
    vector<string*>::iterator itr = FindByCode();
    if (itr == NULL) {
         return EXIT_FAILURE;
    }
}

来源：https://stackoverflow.com/questions/60033865/can-i-return-null-iterator-from-a-function