Olivier Langlois's blog

Which is better

void f(int &a);

or

void f(int *a);

?

Once compiled, there should not be any difference between the 2 versions as references are most likely implemented with pointers under the compiler hood. The main difference between passing a pointer to a function vs a reference is that with the reference you are sure that the reference points to a valid object where as with pointers you could pass a NULL pointer.

Hence, if a NULL pointer is not a valid value for a function, you can enforce that fact by passing a reference. Some people argue that it is possible to have dangling references by doing:

int &f()
{
    int a;
    a = 5;
    return a;
}

int main(int argc, char *argv)
{
    int &r = f();
    return 0;
}

or

int main(int argc, char *argv)
{
    int *p = new int(5);
    int &r = *p;
    delete p;
    return 0;
}

but I consider these cases pathological and my opinion is that references are safer than pointers because:

1. They behave like const pointers.
2. They must be initialized at their declaration.

With these, it should be much harder to have *unintentionally* dangling references than having uninitialized pointers especially if you do not do the newbie mistake of returning a reference to a local variable. My C++ debugging experience has led to me to fix plenty of pointer problems but I have never seen until now a dangling reference problem in real code.

Also, Scott Meyers, in his book More Effective C++ (item 1: Distinguish between pointers and references), goes in the same way about this issue.