Can't Run Macro That Calls 16-bit DLL in 32-bit MS Excel

• Microsoft Excel for Windows NT, version 5.0
• Microsoft Excel for Windows 95, version 7.0
• Microsoft Excel 97 for Windows

SYMPTOMS

When you upgrade to one of the Microsoft Excel versions listed at the beginning of this article from Microsoft Excel version 5.0 for Windows (a 16-bit application), you may have trouble running macros that you created in the previous version of Microsoft Excel. This includes macros written in the Microsoft Excel macro language (XLM), as well as macros written in the Visual Basic for Applications language.

For example, you may receive one of the following error messages:

Version 5.0 for Windows NT and Version 7.0

Run-time error '48': Error in loading DLL

-or-

Run-time error '453':
Function not defined in specified DLL

Version 97

Run-time error '48': File not found: <filename>

- or -

Run-time error '453':
Can't find DLL entry point <function> in <filename>

CAUSE

This problem occurs when you run a macro in a 32-bit version of Microsoft Excel that calls a 16-bit Windows application programming interface (API) or 16-bit Windows dynamic-link library (DLL). For example, if you create a Visual Basic macro in Microsoft Excel version 5.0 for Windows that calls a 16-bit DLL, the macro may return an error message or may not run at all in Microsoft Excel for Windows 95.

If a macro that you created in Microsoft Excel version 5.0 for Windows calls a 16-bit API DLL, you must modify the macro before you can run it in a 32-bit version of Microsoft Excel.

These modifications are necessary because 16-bit API calls and 16-bit DLL calls are not executed correctly from a macro that you run in a 32- bit program.

Note that this is not a problem when you run a macro in Microsoft Excel version 5.0 for Windows (16-bit) under Windows NT or Windows 95, even if the macro calls a 16-bit DLL or API. This is only a problem when you run a macro that calls a 16-bit DLL or API from a 32-bit version of Microsoft Excel.

This is not a limitation of Microsoft Excel. A 32-bit compiled program or code called from a 32-bit program cannot make direct 16-bit API or DLL calls. Additionally, a 16-bit compiled program or code called from a 16-bit program cannot make direct 32-bit API or DLL calls. This limitation in calls between 16-bit and 32-bit layers occurs in both Windows 95 and Windows NT because of the advanced flat-memory-model management systems that these operating environments use; this limitation also occurs because of the way these operating environments load DLLs.

Example

Run-time error '48':
Error in loading DLL

-or-

Run-time error '48':
File not found: <filename>

Declare Function WritePrivateProfileString Lib "KERNEL" _

  (ByVal lpApplicationName As String, ByVal lpKeyName As String, _
  ByVal lpString As String, ByVal lplFileName As String) As Integer
 
Sub ErrorIf32Bit()
 
   Dim charsWritten As Integer
 
   ' Use 16-bit version of API function.
   ' The following two lines should be entered as one line.
 
   charsWritten = WritePrivateProfileString("sectionName", _

      "keyName", "value16", ThisWorkbook.Path & "\myfile.ini")
 
End Sub 

Run-time error '453':
Function not defined in specified DLL

-or-

Run-time error '453':
Can't find DLL entry point <function> in <filename>

RESOLUTION

NOTE: It may be possible to work around this situation by creating a macro that makes calls to the Windows application programming interface (API). This type of programming is supported by the Windows Software Development Kit (SDK) and the Visual Basic, Professional Edition, support groups. The level of support you can receive from these groups depends on the individual support policies of the group. (Microsoft Support professionals may not be able to assist in specific construction of macros that use API programming.) If you have limited programming experience, you may want to consult one of the Microsoft Solution Providers. Solution Providers offer a wide range of fee-based services, including creating custom macros. For more information about Microsoft Solution Providers, call Microsoft Customer Information Service at (800) 426-9400. To modify macros you created in Microsoft Excel version 5.0 for Windows, you must modify your code to make Win32 API calls when you run the macro in a 32-bit version of Microsoft Excel. If this is not possible (for example, if you don't have access to the source code of the DLL), you must modify the macro to "thunk" through an intermediate DLL to make the 16-bit API call.

You can also modify your macro so that it is operating-system independent (that is, so the macro will run in both 16-bit and 32-bit versions of Microsoft Excel and Windows). Note however that this modification is more difficult than modifying your macro so that it will run specifically in a 16-bit or 32-bit version of Microsoft Excel.

NOTE: You do not need to modify code that uses OLE Automation or dynamic data exchange (DDE). All OLE and DDE code will continue to work regardless of whether the programs involved are 16-bit or 32-bit. OLE and DDE insulate automation calls, so all combinations of containers (clients) and servers (16/16, 16/32, 32/16, and 32/32) will work under Windows 95 and Windows NT.

Visual Basic Example

Declare Function WritePrivateProfileString Lib "KERNEL32" Alias _
     "WritePrivateProfileStringA" (ByVal lpApplicationName As String, _
     ByVal lpKeyName As String, ByVal lpString As String, _
     ByVal lplFileName As String) As Long

Declare Function WritePrivateProfileString16 Lib "KERNEL" Alias _
     "WritePrivateProfileString" (ByVal lpApplicationName As String, _
     ByVal lpKeyName As String, ByVal lpString As String, _
     ByVal lplFileName As String) As Integer

Sub MultiOSExample()

   ' Because the different versions of this function return different data
   ' types, this example uses a Variant to receive the return value.

   Dim charsWritten As Variant

   ' Check to see if the string "32-bit" is contained in the name of the
   ' current operating system.

   If InStr(Application.OperatingSystem, "32-bit") Then

      ' If 32-bit is found, use 32-bit version of API function.
      ' The following two lines should be entered as one line.
      charsWritten = WritePrivateProfileString("sectionName", _
          "keyName", "value32", ThisWorkbook.Path & "\myfile.ini")

   Else

      ' If 32-bit is not found, use 16-bit version of API function.
      ' The following two lines should be entered as one line.
      charsWritten = WritePrivateProfileString16("sectionName", _
          "keyName", "value16", ThisWorkbook.Path & "\myfile.ini")

   End If

End Sub

 

MORE INFORMATION

Microsoft Excel for Windows NT Xlreadme.hlp

1. Run the Microsoft Excel Readme Help Contents, Xlreadme.hlp.



2. Click the "Differences between Microsoft Excel for Windows NT and Microsoft Excel for Windows 3.1" help topic.



3. Locate the "Differences for developers of DLLs or XLLs" section in this topic.

Office-Based Solutions to 32-Bit Office

• Which API Should Your Solution Code Call?



• Calling the Win32 API



• Writing a Single Code Base for 16-Bit and 32-Bit Office Applications



• Determining Whether a 32-Bit Application Is Running



• Recompiling DLLs



• Thunking



• Advanced Programming Topics: Translating C API Declarations to Visual Basic or Visual Basic for Applications

Q140619 Contents of the MS Office for Windows 95 Resource Kit

Q120767 Porting 16-Bit WordBasic Macros to 32-Bit WordBasic Macros

Additional query words: 16 bit 32 16bit 32bit

Keywords : kbcode kbprg
Version : WINDOWS:97; Win95:7.0; winnt:5.0
Platform : Win95 WINDOWS winnt
Issue type :