Mega Code Archive

How do I manipulate the computer (shutdown, restart, etc)

Title: How do I manipulate the computer (shutdown, restart, etc)? It can be occasionally useful to do different things to the system within your program that can be done via the log off menu or otherwise. They include: Shutdown, Restart, Log off, Standby, Hibernate, and Power Off. These things will be described below: System Privileges Many of these things require the setting of SeShutdownPrivilege. For what I do, I ended up borrowing the code that you will find at Torry's Delphi Pages. Any code samples which require it will have the NTSetPrivilege function call that is found on that page. Shutdown All these functions involve variations of two system calls. This will start the first group. Shutting down the system involves a call to ExitWindowsEx. Delphi will have this procedure defined within the Windows unit, so all that is needed is to call the function. The first parm is an action, the second one is reserved and can always be 0. To shutdown the system: CODE procedure machine_shutdown; const SE_SHUTDOWN_NAME = 'SeShutdownPrivilege'; begin NTSetPrivilege(SE_SHUTDOWN_NAME, True); ExitWindowsEx(EWX_SHUTDOWN or EWX_FORCE, 0); end; the first parm value is obvious, the second is not. In the Win32 help dll, the following is said about EWX_FORCE: Quote: Forces processes to terminate. Instead of bringing up the "application not responding" dialog box for the user, this value forces an application to terminate if it does not respond. Restart This code restarts a computer: CODE procedure machine_restart; const SE_SHUTDOWN_NAME = 'SeShutdownPrivilege'; begin NTSetPrivilege(SE_SHUTDOWN_NAME, True); ExitWindowsEx(EWX_REBOOT or EWX_FORCE, 0); end; Logoff This code logs off the current user: CODE procedure machine_logoff; const SE_SHUTDOWN_NAME = 'SeShutdownPrivilege'; begin NTSetPrivilege(SE_SHUTDOWN_NAME, True); ExitWindowsEx(EWX_LOGOFF or EWX_FORCE, 0); end; Power Off This code powers down the system. This is distinguished from the shut down command in that it will power off the system, while the shut down command will just put the computer to a point where it can be turned off. CODE procedure machine_poweroff; const SE_SHUTDOWN_NAME = 'SeShutdownPrivilege'; begin if IsPwrShutdownAllowed then begin NTSetPrivilege(SE_SHUTDOWN_NAME, True); ExitWindowsEx(EWX_POWEROFF or EWX_FORCE, 0); end else MessageDlg('Soft Power Off not supported on this system.', mtWarning, [mbOK], 0); end; IsPwrShutdownAllowed is described later. Lock the Workstation To lock the workstation, requiring the password if set is: CODE function LockWorkStation: boolean; stdcall; external 'user32.dll' name 'LockWorkStation'; procedure machine_lock; begin if not LockWorkStation then MessageDlg('System not locked successfully.', mtWarning, [mbOK], 0); end; Standby This group starts the actions involving the other system function. I notice it is not defined in Delphi 3 (and perhaps not future Delphis), so I will show the definitions below for all the functions of interest: CODE function SetSuspendState(hibernate, forcecritical, disablewakeevent: boolean): boolean; stdcall; external 'powrprof.dll' name 'SetSuspendState'; function IsHibernateAllowed: boolean; stdcall; external 'powrprof.dll' name 'IsPwrHibernateAllowed'; function IsPwrSuspendAllowed: Boolean; stdcall; external 'powrprof.dll' name 'IsPwrSuspendAllowed'; function IsPwrShutdownAllowed: Boolean; stdcall; external 'powrprof.dll' name 'IsPwrShutdownAllowed'; The function names are quite obvious as to their functionality. To look at SetSuspendState, I will quote from the SDK regarding the parms: Quote: Hibernate If this parameter is TRUE, the system hibernates. If the parameter is FALSE, the system is suspended. ForceCritical If this parameter is TRUE, the system suspends operation immediately; if it is FALSE, the system broadcasts a PBT_APMQUERYSUSPEND event to each application to request permission to suspend operation. DisableWakeEvent If this parameter is TRUE, the system disables all wake events. If the parameter is FALSE, any system wake events remain enabled. To put the system into standby mode, do this: CODE procedure machine_standby; begin if IsPwrSuspendAllowed then SetSuspendState(false, false, false) else MessageDlg('System Standby not supported on this system.', mtWarning, [mbOK], 0); end; Hibernate To put the system into hibernate, do this: CODE procedure machine_hibernate; begin if IsHibernateAllowed then SetSuspendState(true, false, false) else MessageDlg('System Hibernate not supported on this system.', mtWarning, [mbOK], 0); end;