ACC: How to Retrieve Windows for Workgroups User Information

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Windows for Workgroups includes a function called NetWkstaGetInfo() that returns information about a computer. This function is especially useful for multiuser applications.

The following procedure explains how to use Access Basic and several Windows API calls to gain access to the NetWkstaGetInfo() function:

1. Create a new module containing the following declarations and functions:
   
   NOTE: In the following sample code, an underscore (_) is used as a line- continuation character. Remove the underscore from the end of the line when re-creating this code in Access Basic.
   
   NOTE: You may have some Microsoft Windows API functions defined in an existing Microsoft Access library; therefore, your declarations may be duplicates. If you receive a duplicate procedure name error message, remove or comment out the declarations statement in your code.
   
   NOTE: Make sure to choose the Compile All command from the Run menu to verify that you do not receive any compilation errors.
   

         Option Explicit
         Declare Function NetWkstaGetInfo% Lib "NetAPI.DLL" (ByVal lServer&, _
            ByVal sLevel%, ByVal pbBuffer&, ByVal cbBuffer%, pcbTotalAvail%)
         Declare Function GlobalAlloc% Lib "Kernel" (ByVal fFlags%, _
            ByVal nSize&)
         Declare Function GlobalLock& Lib "Kernel" (ByVal hMem%)
         Declare Function GlobalUnlock% Lib "Kernel" (ByVal hMem%)
         Declare Function GlobalFree% Lib "Kernel" (ByVal hMem%)
         Declare Sub lstrcpy Lib "Kernel" (ByVal dest As Any, _
            ByVal src As Any)
         Declare Sub hmemcpy Lib "Kernel" (ByVal dest As Any, _
            ByVal src As Any, ByVal size As Long)
   
         Function GetBinInt (sobj As String, off As Integer)
            If (Asc(Mid$(sobj, off + 1, 1)) < 128) Then
               GetBinInt = Asc(Mid$(sobj, off, 1)) +_
                               Asc(Mid$(sobj, off + 1, 1)) * 256
            Else
               GetBinInt = ((&HFF - Asc(Mid$(sobj, off + 1, 1))) * 256) - _
                             Asc(Mid$(sobj, off, 1))
            End If
         End Function
   
         Function GetWorkstationInfo (sComputer As String, _
            sUserName As String, sWorkgroup As String, sLogonDomain As String)
            Dim nRetSize As Integer, nStruct, ret As Integer, dummy As Integer
            Dim hMem As Integer, lpMem As Long, sTemp As String
   
            ' Get the size of the return structure.
            ret = NetWkstaGetInfo(0&, 10, 0&, 0, nRetSize)
            If (ret <> 0) And (ret <> 2123) Then
               GetWorkstationInfo = False
               Exit Function
            End If
   
            ' Allocate memory for the structure.
            hMem = GlobalAlloc(0, CLng(nRetSize))
            nStruct = nRetSize
            If (hMem <> 0) Then
               lpMem = GlobalLock(hMem)
   
               ' Read workstation information into structure.
               ret = NetWkstaGetInfo(0&, 10, lpMem, nRetSize, nRetSize)
               If (ret = 0) Then
                  sTemp = Space(100)
                  hmemcpy sTemp, lpMem, nStruct
   
                  ' Retrieve the computer name.
                  sComputer = Space(100)
                  lpMem = CLng(GetBinInt(sTemp, 1)) +_
                              (CLng(GetBinInt(sTemp, 3)) * CLng(&H10000))
                  lstrcpy sComputer, lpMem
                  sComputer = Mid(sComputer, 1, InStr(sComputer, Chr(0)) - 1)
   
                  ' Retrieve the user name.
                  sUserName = Space(100)
                  lpMem = CLng(GetBinInt(sTemp, 5)) +_
                              (CLng(GetBinInt(sTemp, 7)) * &H10000)
                  lstrcpy sUserName, lpMem
                  sUserName = Mid(sUserName, 1, InStr(sUserName, Chr(0)) - 1)
   
                  ' Retrieve the workgroup name.
                  sWorkgroup = Space(100)
                  lpMem = CLng(GetBinInt(sTemp, 9)) +_
                              (CLng(GetBinInt(sTemp, 11)) * &H10000)
                  lstrcpy sWorkgroup, lpMem
                  sWorkgroup = Mid(sWorkgroup, 1, InStr(sWorkgroup, _
                                                        Chr(0)) - 1)
   
                  ' Retrieve the logon domain name.
                  sLogonDomain = Space(100)
                  lpMem = CLng(GetBinInt(sTemp, 15)) +_
                              (CLng(GetBinInt(sTemp, 17)) * &H10000)
                  lstrcpy sLogonDomain, lpMem
                  sLogonDomain = Mid(sLogonDomain, 1, InStr(sLogonDomain, _
                                     Chr(0)) - 1)
               End If
               ' Free the memory allocated.
               dummy = GlobalUnlock(hMem)
               dummy = GlobalFree(hMem)
            Else
               ret = -1
            End If
            GetWorkstationInfo = IIf(ret = 0, True, False)
         End Function
   						

2. Test this function by creating the following Access Basic function:
   

         Sub ShowInfo ()
            Dim a$, b$, c$, d$
   
            If GetWorkstationInfo(a$, b$, c$, d$) Then
               MsgBox a$ & " " & b$ & " " & c$ & " " & d$
            Else
               MsgBox "Unable to get information."
            End If
         End Sub
   						

3. In the Immediate window, type the following, and the press ENTER:
   
   ShowInfo

Note that either a dialog box displaying information about the computer, or, if you are running this function on a non-Windows for Workgroups computer, an error message stating "Unable to get information" is displayed.