Delete NULL but no compile error

Question

I\'m confused why the following C++ code can compile. Why does a call to delete the method of 0 not produce any error?!

int *arr = NULL;     // or if I use 0         


        

Answer 1

Although your example is trivial, there is no way for a compiler to know (at compile time) the value of a pointer.

You can also dereference null at compile time:

// this code compiles
Object* pObject = 0;
pObject->SomeMethod();

Compilers aren't built to handle these kinds of error conditions at compile time.

And most (all?) implementations have 'delete 0' as a non-operation. This code should run fine:

Object* pObject = new Object();
delete pObject;
pObject = 0;
delete pObject;

Although I'm not 100% sure on that :)