8.54. SysShutdownSystem (Windows only)

Warning

Once this function has been called, the initiated shutdown cannot be aborted—data loss may occur!

Provides an interface to the InitiateSystemShutdown() API on Windows. If the user has sufficient privileges, this function can be used to shut down the local machine or a remote system. In general all users have sufficient privileges to shut down the local machine and only Administrators have sufficient privileges to shut down remote machines.

The user of this function is strongly encouraged to read the Microsoft documentation for InitiateSystemShutdown() to understand the finer points to using this function. The documentation is freely available online. A Google search using InitiateSystemShutdown MSDN will provide a link to the documentation. In particular, this function can be used to force a shut down of a system while users are logged on and applications have unsaved data.

If the timeout argument is not 0, a shut down dialog is displayed on the machine being shut down, naming the user who initiated the shut down, a timer counting down the seconds until the machine is shut down, and prompting the user to log off. This dialog can be moved but it can not be closed and remains on top of all other windows on the system.

If any open application has unsaved data, the operating system gives the application a chance to prompt the user to save and close the application. If the force argument is false, the shut down will be delayed until the user responds, and ultimately the user could cancel the shut down. If the force argument is true the system will force the application closed whether the data gets saved or not. The application is still given a chance to prompt the user to save the data, but the user only has a few seconds to respond before the system forcibly closing the application.

The implications of the preceding two paragraphs are this, if the timeout argument is 0 and the force argument is true, the system immediately shuts down and any unsaved data is forever lost. This is why the user of this function is encouraged to fully understand this function before using it.

Parameters:

computer: Indicates which system to shut down. If omitted or the empty string, the local machine is shut down. Otherwise this should be the network name of the remote machine.
message: An additional message that is added to the shut down dialog. If omitted, no additional message is added.
timeout: The time, in seconds, before the system is shut down. If this value is 0, the system is immediately shut down and no shut down dialog is displayed. The shut down can not be aborted. If omitted the default time out is 30 seconds.
force: If this argument is true, applications with unsaved data will be forced close by the system whether the data is saved or not. If false, the shut down is delayed until applications with unsaved data responds. If an application does not respond, the user will be prompted by the system to end the application. At this point, if the user chooses not to forcibly end the application, the shut down will be aborted.
Please note some consequences of this argument as described by Microsoft. If this argument is false, i.e. applications are not forced to close, and an application with unsaved changes is running on the console session, the shutdown will remain in progress until the user logged into the console session aborts the shutdown, saves changes, closes the application, or forces the application to close. During this period, the shutdown may not be aborted except by the console user, and another shutdown may not be initiated. Using true for this argument prevents that situation. But, using true can also result in unsaved data being lost.
reboot: If this argument is true, the system is rebooted after the shut down. If it is false, the system is shut down. The default if omitted is false.

Returns:

Returns 0 for success or a Windows System Error code for failure. For instance a return of 1300 would indicate the user does not have sufficient privileges to shut down the named system. Use SysGetErrorText to get a generic text description for any Windows System Error code. For example, the description for error code 1300 is Not all privileges referenced are assigned to the caller.