DLL Hell Programming

[sans-hubris]

I'm not really sure which section this should be in since it encompasses multiple languages (specifically C++ and VB6.0.)

I'm pretty sure that to convert between a VB String and a C++ string you use the MFC CString class. Is this correct?

How do you use a struct defined in C++ inside a VB application? Do you create a Collection?

[stuka]

The datatype in C/C++ for the VB string is, I think, a BSTR (and there are conversion methods to/from a CString). As for structs, VB has a struct-like thing - syntax:Type typename
fieldname1 AS datatype
fieldname2 AS datatype
End Type

My guess is that you'd need this for a struct.

Oh..looked this up in MSDN:In general, use the ByVal keyword when passing string arguments to DLL procedures that expect LPSTR strings. If the DLL expects a pointer to an LPSTR string, pass the Visual Basic string by reference.

(Note that LPSTR is either a char* or wchar*, depending on platform, etc.)

[kmj]

yeah, BSTR is what VB strings are in C++, or _bstr_t .. kind of the same thing. MS sucks, they make life hell for C++ programmers trying to use VB shit. IMO.