Could I ever want to access the address zero?

Question

The constant 0 is used as the null pointer in C and C++. But as in the question \"Pointer to a specific fixed address\" there seems to be some possible use of assigning fixe

Answer 1

Writing to address zero can be done, but it depends upon several factors such as your OS, target architecture and MMU configuration. In fact, it can be a useful debugging tool (but not always).

For example, a few years ago while working on an embedded system (with few debugging tools available), we had a problem which was resulting in a warm reboot. To help locate the problem, we were debugging using sprintf(NULL, ...); and a 9600 baud serial cable. As I said--few debugging tools available. With our setup, we knew that a warm reboot would not corrupt the first 256 bytes of memory. Thus after the warm reboot we could pause the loader and dump the memory contents to find out what happened prior to reboot.