Question

Possible Duplicate:
A reference can not be NULL or it can be NULL?

How does the below program compile successfully?

int main()
{
   int *ptr = NULL;
   int &ref = *ptr;
   return 0;
}

See it on ideone.

Can we define reference to NULL?

Answer 1

The code you’ve given will compile, because the compiler doesn’t check the value of the pointer at compile-time. However dereferencing a NULL pointer is undefined behavior.

This is a problem that I ran into once in the past and was burned into my memory. My further thoughts can be found here: https://stackoverflow.com/a/57656/5987