Microsoft KB Archive/176695

= PRB: ExitWindowsEx API Does Not Reboot Windows NT =

Article ID: 176695

Article Last Modified on 6/24/2004

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APPLIES TO


 * Microsoft Visual Basic 5.0 Learning Edition
 * Microsoft Visual Basic 6.0 Learning Edition
 * Microsoft Visual Basic 5.0 Professional Edition
 * Microsoft Visual Basic 6.0 Professional Edition
 * Microsoft Visual Basic 5.0 Enterprise Edition
 * Microsoft Visual Basic 6.0 Enterprise Edition
 * Microsoft Visual Basic 4.0 Standard Edition
 * Microsoft Visual Basic 4.0 Professional Edition
 * Microsoft Visual Basic 4.0 32-Bit Enterprise Edition

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This article was previously published under Q176695



SYMPTOMS
When you use the ExitWindowsEx API to reboot the system under Windows NT and Windows 2000, the machine does not reboot.



CAUSE
In order to programmatically reboot a Windows NT or Windows 2000 system, the process requires the SE_SHUTDOWN_NAME privilege. By default, Visual Basic applications do not have this privilege and therefore will not reboot the machine.



RESOLUTION
In order to get ExitWindowsEx API to reboot the system under Windows NT or Windows 2000, the SE_SHUTDOWN_NAME privilege must be set. The following steps describe how to get the ExitWindowsEx API to work under Windows NT and Windows 2000.

Step By Step Example
 Create a new standard EXE in Visual Basic. Form1 is created by default.  View the code for Form1. In the Declarations section, add the following code: Private Type LUID UsedPart As Long IgnoredForNowHigh32BitPart As Long End Type

Private Type TOKEN_PRIVILEGES PrivilegeCount As Long TheLuid As LUID Attributes As Long End Type

Private Const EWX_SHUTDOWN As Long = 1 Private Const EWX_FORCE As Long = 4 Private Const EWX_REBOOT = 2

Private Declare Function ExitWindowsEx Lib "user32" (ByVal _          dwOptions As Long, ByVal dwReserved As Long) As Long

Private Declare Function GetCurrentProcess Lib "kernel32" As Long Private Declare Function OpenProcessToken Lib "advapi32" (ByVal _        ProcessHandle As Long, _         ByVal DesiredAccess As Long, TokenHandle As Long) As Long Private Declare Function LookupPrivilegeValue Lib "advapi32" _ Alias "LookupPrivilegeValueA" _ (ByVal lpSystemName As String, ByVal lpName As String, lpLuid _        As LUID) As Long Private Declare Function AdjustTokenPrivileges Lib "advapi32" _ (ByVal TokenHandle As Long, _        ByVal DisableAllPrivileges As Long, NewState As TOKEN_PRIVILEGES _        , ByVal BufferLength As Long, _      PreviousState As TOKEN_PRIVILEGES, ReturnLength As Long) As Long

  Add a procedure called AdjustToken with the following code: Private Sub AdjustToken Const TOKEN_ADJUST_PRIVILEGES = &H20 Const TOKEN_QUERY = &H8 Const SE_PRIVILEGE_ENABLED = &H2 Dim hdlProcessHandle As Long Dim hdlTokenHandle As Long Dim tmpLuid As LUID Dim tkp As TOKEN_PRIVILEGES Dim tkpNewButIgnored As TOKEN_PRIVILEGES Dim lBufferNeeded As Long

hdlProcessHandle = GetCurrentProcess OpenProcessToken hdlProcessHandle, (TOKEN_ADJUST_PRIVILEGES Or _           TOKEN_QUERY), hdlTokenHandle

' Get the LUID for shutdown privilege. LookupPrivilegeValue "", "SeShutdownPrivilege", tmpLuid

tkp.PrivilegeCount = 1   ' One privilege to set tkp.TheLuid = tmpLuid tkp.Attributes = SE_PRIVILEGE_ENABLED

' Enable the shutdown privilege in the access token of this process. AdjustTokenPrivileges hdlTokenHandle, False, _ tkp, Len(tkpNewButIgnored), tkpNewButIgnored, lBufferNeeded

End Sub

  Add a CommandButton to the form. In the Click event, add the following code: Private Sub Command1_Click AdjustToken ExitWindowsEx (EWX_SHUTDOWN Or EWX_FORCE Or EWX_REBOOT), &HFFFF End Sub

 Save the project and build an executable. When you run the executable and click the CommandButton the computer will reboot as expected.

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STATUS
This behavior is by design.

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