title: Could I ever want to access the address zero?
body: <p>The constant 0 is used as the null pointer in C and C++. But as in the question <a href="https://stackoverflow.com/questions/2389251/pointer-to-a-specific-fixed-address"><em>"Pointer to a specific fixed address</em>"</a> there seems to be some possible use of assigning fixed addresses. Is there ever any conceivable need, in any system, for whatever low level task, for accessing the address 0?</p>
  
  <p>If there is, how is that solved with 0 being the null pointer and all?</p>
  
  <p>If not, what makes it certain that there is not such a need?</p>