What real platforms map hardware ports to memory addresses?

Question

I sometimes see statements that on some platforms the following C or C++ code:

int* ptr;
*ptr = 0;

can result in writing to a hardware input-ou

Answer 1

You can do this in modern Windows (and I'm pretty sure Linux offers it too). It's called memory mapped files. You can load a file into memory on Windows and then write/alter it just by manipulating pointers.