Question: I have a callback function which gets called when a hardware interrupt is generated. But when I build my code I am getting "expression has no effect"

```
void registerCallBack(int originator,uint32* cbackFunction)
{
    Originator[originator].callback = cbackFunction;
}

// interrupt calls the following function
void callbackFunction(int originator)
{

    Originator[originator].callback;  // throwing warning here
}

```

Answer: 
Call the function

```
void callbackFunction(int originator)
{

    Originator[originator].callback();  //parenthesis
}

```
Shouldn't it simply be 

```
Originator[originator].callback();

```

so that the callback is actually invoked?