CODEWITHSUNDEEP
c++functionpointers
Abhishek
Abhishek

Reputation: 1837

Pointer Function

Can someone explain what this actually represents ?

Foo *getfoo()
{
    return foo_object;
}

Foo here is a class. My question is what does the pointer before the function name represents?

Upvotes: 0

Views: 173

Answers (4)

kamituel
kamituel

Reputation: 35970

As others noted, 'Foo *' syntax means function is returning a pointer to a place in the memory, not an object itself.

It has the implications that, if you get this pointer, this means getfoo() could've allocated memory for it. Thus it's possible you will have to free it yourself, otherwise this memory will be allocated for the whole time your program is running. This is called a memory leak.

Here is an example with freeing memory:

class Foo {};

Foo *getfoo() {
  Foo *f = new Foo();  // Memory allocated here
  return f;
}

int main () {
  Foo *g = getfoo();
  // some code here

  delete(g); // free the memory as "g" is no longer needed.

  return 0;
}

In C++ it's crucial that you learn to manage memory. Otherwise, sooner or later, your apps will fail. There are some programming patterns helping with that, of which the most popular is smart pointers.

Upvotes: 1

Vijay
Vijay

Reputation: 67301

It means that the function returns a pointer. and what type that pointer is what is mentioned before the pointer. that is the pointer will be of type Foo.Foo here is as you said is a class and the function returns a class object pointer.

Upvotes: 1

aaaaaa123456789
aaaaaa123456789

Reputation: 5852

Some people like to add the asterisk right before the name. I personally prefer this syntax:

Foo * getfoo () {
  return foo_object;
}

I think that shows a bit more clearly that Foo * is just the type the function returns (just like it could be int).

Upvotes: 1

Anshul
Anshul

Reputation: 1446

getfoo functions returns a an object pointer(of class foo)

Upvotes: 0

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