"Paul" wrote:
[Assuming VB 6]
A VB DLL is an ActiveX DLL, so you can use it just like any other COM
library. Since you mention Visual C++, you can use the #import directive.
You just need to remember that a VB class has a default interface named
_"Class Name". The quick example I just ran:
- Created an ActiveX DLL project in VB named testlib.
- Add a class named test_class (thus the interface will be named
_test_class)
- Add the following function:
Public Function DblStr(ByVal s As String) As String
DblStr = s & s
End Function
- Make the DLL
- Write the following C++ (note: compiled with VC 7, not 6, but it should
work)
#include <windows.h>
#include <string>
#include <iostream>
//This works because VB embeds the typelib in the DLL
#import "testlib.dll" no_namespace
using namespace std;
int main(void)
{
CoInitialize(NULL);
_test_classPtr t;
t.CreateInstance("testlib.test_class");
string s = t->DblStr("Howdy");
cout << "Howdy doubled is : " << s << endl;
t.Release();
CoUninitialize();
return 0;
}
- Build with cl /GX test.cpp
- Output was
Howdy doubled is : HowdyHowdy
Of course, I ignored all errors and problems (I didn't check for a
_com_error exception getting thrown, the _bstr_t char* operator I used to
create string s could have returned a NULL which would have been bad, etc,
etc).
Craig
