c++ change pointer passed as argument

To change the pointer passed in argument you need something like this:

void foo(int **ptr) //pointer to pointer
{
    *ptr = new int[10]; //just for example, use RAII in a real world
}

or

void bar(int *& ptr) //reference to pointer (a bit confusing look)
{
    ptr = new int[10];
}

Original thread:  http://stackoverflow.com/questions/11842416/function-does-not-change-passed-pointer-c