BBC BASIC Programmers' Reference

by Richard Russell, October 2007

It's not a very likely thing to want to do, but the code below shuts down the PC when executed. Note that if run under Windows 2000 Professional, Windows XP Professional or Windows Vista it's entirely likely that the system adminstrator will have disabled the ability of ordinary user programs to shut down the PC. In that case the program will fail with the Cannot acquire Shutdown privilege message.

        REM. Caution: this program shuts down the computer!
 
        SYS "GetCurrentProcess" TO hprocess%
 
        _TOKEN_ADJUST_PRIVILEGES = &20
        _TOKEN_QUERY = 8
        SYS "OpenProcessToken", hprocess%, \
        \                _TOKEN_ADJUST_PRIVILEGES OR _TOKEN_QUERY, ^htoken%
 
        _SE_PRIVILEGE_ENABLED = 2
        DIM tkp{PrivilegeCount%, Luid{l%,h%}, Attributes%}
        tkp.PrivilegeCount% = 1
        tkp.Attributes% = _SE_PRIVILEGE_ENABLED
 
        SYS "LookupPrivilegeValue", "", "SeShutdownPrivilege", ^tkp.Luid.l%
        SYS "AdjustTokenPrivileges", htoken%, 0, tkp{}, 0, 0, 0 TO ok%
        IF ok% = 0 ERROR 100, "Cannot acquire Shutdown privilege"
 
        _EWX_POWEROFF = 8
        SYS "ExitWindowsEx", _EWX_POWEROFF, &FFFF TO ok%
        IF ok% PRINT "System shutting down...."

You may alternatively wish to change the _EWX_POWEROFF value to _EWX_SHUTDOWN (“=1”) which doesn't turn the power off or _EWX_REBOOT (“=2”) which restarts the system.