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c++pointersdouble-pointer

Another option to double pointer

How could I send a pointer to a function with reference? I mean, I would like to change where the pointer is poiting in that function.

I have seen for this the double pointer, like for example:

Abc* p;
function(&p);

function(Abc** p){
  (*p) = 0;
}

But, I have been told that this is not the best way to approach it. How could be better? Would this work? :

Abc* p;
function(p);

function(Abc* p){
  p = 0;
}

Thanks

Solution

  • No, that will not work. That will copy the value of p into the function and then only modify that copy.

    The most appropriate way to pass something by reference in C++ is to use a reference type. They are denoted with an ampersand in the type. You could take a reference to pointer:

    Abc* p;
function(p);

void function(Abc*& p){
  p = 0;
}

    This means that, even though you passed p directly, it is not copied into the function. The p argument is a reference to the object passed in.