Restart a computer using function pointers in C

Question

I was learning about function pointers in C when I came across a program that restarts the computer upon execution.

void (*f) (void);
f=(void (*)(void) MK_FP(0xF         


        

Answer 1

This is a system dependent (ie: non-portable) approach to restarting the machine. What is the intended OS for this program to run on? Is it DOS (I'm assuming). Try running it inside a virtual machine and find out.

If you want this to work on other platforms, you'll need to write some platform specific stuff, like so:

#ifdef __linux__
  system("shutdown -P now");
#elif _WIN32
  #if (WINVER == NTDDI_WIN7) // Windows 7
    system("C:\\WINDOWS\\System32\\shutdown /s");
  #endif
  #if ((WINVER <= NTDDI_WINXPSP3) && (WINVER >= NTDDI_WINXP)) // Windows XP
    system("C:\\WINDOWS\\System32\\shutdown -s");
  #endif
#else
  #error System not recognized
#endif