# Administration user defined functions Reference

Below is a complete list of the user defined functions available in AutoIt. Click on a user defined function name for a detailed description.

When using them you need to add a #include <WinAPISys.au3>.

User Defined Function | Description
--- | ---
_WinAPI_LockWorkStation | Locks the workstation's display
_WinAPI_ShutdownBlockReasonCreate | Indicates that the system cannot be shut down and sets a reason string to be displayed to the user if system shutdown is initiated
_WinAPI_ShutdownBlockReasonDestroy | Indicates that the system can be shut down and frees the reason string
_WinAPI_ShutdownBlockReasonQuery | Retrieves the reason string set by the _WinAPI_ShutdownBlockReasonCreate() function