All,

I have searched the archives here as well as other resources and I am still having an issue with calling a function in a C++ dll from VB. I have pasted the VB test code that I am using and the C++ function declare below in hopes that some one can spot something that I am doing wrong.

When running the test code the dll loads successfully but a call to the TestScript() function raises the error "Can't find DLL entry point test_vbscript in C:\Mcam91\Chooks\vbscript.dll" I have tried a number of things including declaring the TestScript function to return an integer or a long and in both cases makes not apparent difference. We have also tried with and without declaring __declspec in the C++ declaration.

I am running XP Pro, VB6, VC6++

' -- Module Declares
Public Declare Function TestScript Lib "C:\Mcam91\Chooks\vbscript.dll" Alias "test_vbscript" () As Integer
Public Declare Function LoadLibrary Lib "kernel32" Alias "LoadLibraryA" (ByVal lpLibFileName As String) As Long
Public Declare Function FreeLibrary Lib "kernel32" (ByVal hLibModule As Long) As Long
Public Const DEF_SCRIPT_DLL                 As String = "C:\Mcam91\Chooks\vbscript.dll"



Public Sub Main()

On Error GoTo PROC_ERR

Dim lngRet          As Long
Dim ret               As Integer

' -- Works as expected
lngRet = LoadLibrary(DEF_SCRIPT_DLL)


If lngRet <> 0 Then
  ' -- Should call a simple messagebox
  Call TestScript '<- Raises error
  ' -- Check
  If ret = 0 Then
     MsgBox "Call to TestScript failed    ", vbExclamation, "DLL Test"
  Else
      ' Add code...
  End If
Else
  MsgBox "Could not load dll '" & DEF_SCRIPT_DLL & "'      ", vbExclamation, "DLL Test"
End If


PROC_EXIT:
' -- Clean up
If lngRet <> 0 Then FreeLibrary lngRet
Exit Sub

PROC_ERR:
Err.Source = "modCode::Main(Sub)"
MsgBox Err.Description & vbCrLf & vbCrLf & _
       "Error Number " & Err.Number & vbCrLf & _
       "Error Source " & Err.Source & "       ", vbExclamation, "DLL Test"
       Debug.Print Err.Description
Resume PROC_EXIT
End Sub

/////// C++ Code Begins /////////

/* __________ test_vbscript __________ */


__declspec(dllexport) int __stdcall test_vbscript(void)
{
int iRet = MessageBox (NULL, "Success", "VBScript test", MB_OK);
CString str("AfxMessageBox text");
iRet = AfxMessageBox(str, MB_SETFOREGROUND);
return(99); // for testing
}

/////// C++ Code Ends /////////

[OnErr0r]

I see a couple problems right off, or at least potential problems.

__declspec(dllexport) int __stdcall test_vbscript(void)

1) The call returns an int in C++, this is a Long in VB.

2) You need a .def file so there is no name mangling, this is likely why VB cannot find the function name.


The .def file only needs:

Library
DllName

Exports
test_vbscript

Also, this is sufficient in the C++ function definition:

int __stdcall test_vbscript(void)

OnErr0r,

The .def was it, thank you very much!!