CODEWITHSUNDEEP
vbavb664-bit32bit-64bit
鄭有維
鄭有維

Reputation: 265

How can I declare function without ptrsafe in 64bit environmnet?

My vb6 program was running on 32bit. Now I have to move it to 64bit.

The lib that I declare below code,the system seem can't get it. Declare:

Public Declare Function LogonUser Lib "advapi32.dll" _
Alias "LogonUserA" (ByVal lpszUsername As String, _
ByVal lpszDomain As String, ByVal lpszPassword As String, _
ByVal dwLogonType As Long, ByVal dwLogonProvider As Long, _
phToken As Long) As Long

Public Declare Function ImpersonateLoggedOnUser Lib "advapi32.dll" (ByVal hToken As Long) As Long
Public Declare Function RevertToSelf Lib "advapi32.dll" () As Long
Public Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long

Run Code:

Public Sub Logon(ByVal strAdminUser As String, ByVal _
    strAdminPassword As String, ByVal strAdminDomain As String)
    Dim lngTokenHandle As Long
    Dim lngLogonType As Long
    Dim lngLogonProvider As Long
    Dim blnResult As Boolean

    lngLogonType = 2
    lngLogonProvider = 0

    blnResult = RevertToSelf()

    blnResult = LogonUser(strAdminUser, strAdminDomain, strAdminPassword, _
    lngLogonType, lngLogonProvider, _
    lngTokenHandle)

    blnResult = ImpersonateLoggedOnUser(lngTokenHandle)
    CloseHandle (lngTokenHandle)

End Sub

I got the error message

Error 91:Object variable or With block variable not set

Almost people say need to add "ptrsafe" after Declare but there is no ptrsafe in vb6.

How can I declare function lib without "ptrsafe" in the 64bit and vb6 ?

Upvotes: 2

Views: 2603

Answers (3)

thx1138v2
thx1138v2

Reputation: 576

Since you are talking about API declarations the following may be helpful. VB6 does not recognize the LongLong data type (64-bit integer) but it can be faked by using the VB6 Currency data type. The Currency numbers are actually stored as 64-bit integers. The four decimal places are only shown in display by dividing the actual number by 10,000. Depending on the specific API calls you are using, you may need to have dual API declarations and select the correct one at run time. So you also need to be able to detect the "bitness" of the system running.

See the following links:

Detect Bitness

Faking 64-bit Integers

Upvotes: 0

Giorgio Brausi
Giorgio Brausi

Reputation: 414

Your functions declarations are wrong. You don't have to add the complete path for Lib, only the library name is need. By add the path, your code fails on 32 bit OS environment, because "C:\Windows\SysWOW64 folder doesn't exists on 32 bit systems.

Public Declare Function LogonUser Lib "advapi32.dll" _
Alias "LogonUserA" (ByVal lpszUsername As String, _
ByVal lpszDomain As String, ByVal lpszPassword As String, _
ByVal dwLogonType As Long, ByVal dwLogonProvider As Long, _
phToken As Long) As Long

   Public Declare Function ImpersonateLoggedOnUser Lib "advapi32.dll" (ByVal hToken As Long) As Long

   Public Declare Function RevertToSelf Lib "advapi32.dll" () As Long

   Public Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long

See: https://support.microsoft.com/en-us/help/248187/how-to-impersonate-a-user-from-active-server-pages

Upvotes: 1

Alex K.
Alex K.

Reputation: 175816

Almost people say need to add "ptrsafe" after Declare but there is no ptrsafe in vb6. How can I declare function lib without "ptrsafe" in the 64bit and vb6 ?

VBA needs to be able to deal with 64 bit Windows when its run within a 64 bit application such as one of the programs from the 64 bit Office suite.

VB6 runs on its own forever & always as a 32 bit process, it does not need to be 64 bit aware as 64 bit Windows happily emulates 32 bit code with no additional steps required.

Because of this pointer-safe types are not needed, use the 32 bit convention (Long) in VB6.

Upvotes: 7

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