I am basically an expert in VB but now I started out with C++. The mistake I made was going with Borland and not Visual C++. I want to convert functions from my VB game into a dll so to speed up the game by a couple of fps. This however is quite impossible in borland. I don''t know why but I get the error "[function name] entry point not found in [dll name]" This absolutely sux as I went through everything possible (all help + forums I could find). I am using "extern "C" __declspec(dllexport)..." but this doesn''t work either. I am at the point where I destroy everything that is Borland, I will uninstall it in a couple of days unless someone can help me. here is one function float __stdcall UPDATE_X(float x, float speed, float elaps, float mov){ return (x - (speed * elaps) * mov) } I want this in a dll, which I did but it can''t be called out. If anybody can make me a basic dll where this can be called out from VB then please e-mail me at "nuke_bot_5d@yahoo.ca". Please do make sure it is in Borland, and that you include the source(I will never be able to learn if this isn''t included) Thanx, I am, 1 error/warning away from destroying everything that is borland in my house + every where else I see it.

Well, I haven''t used C++ Builder, but I have used Delphi.Go to c++ builder''s help. I am sure it has a small tutorial inside fro writing DLLs (Delphi has, so c++ builder must have it too).

If this doesn''t help, then i am sure that your problem is in the calling convention of the function you have written. Again, go to c++ builder''s help and check all the function calling conventions available there. Compare them with the calling convention of VB functions and choose the correct calling convention for your functions in C++ Builder.

I have a full book on C++ (it came with Borland) called C++ in 21 days. I have gone through that book, the C++ help files, internet forums and everything else I can think off. Now it is time to burn the Borland CD.

I don''t know anything about Borland C, but I got your function working in a Visual C++ DLL project:

In .C file:

float __declspec(dllexport) __stdcall UPDATE_X(float x, float speed, float elaps, float mov)
{
return (x - (speed * elaps) * mov);
}

In VB file:

Declare Function UPDATE_X Lib "testdllname.dll" Alias "_UPDATE_X@16" (ByVal x As Single, ByVal speed As Single, ByVal elaps As Single, ByVal mov As Single) As Single

...

Debug.Print UPDATE_X(20.5, 10.3, 3.5, 2.5)


The important thing is to work out what the function name will end up as in the DLL for your VB Declare statement, for more information on this do a google search for: DLL Name mangling C VB.

The name mangling that takes place on your function is:
1. prefixed with _
2. suffixed with @
3. further suffixed with the total number of bytes of the sizeofs the function parameters (i.e. 4 floats = 4 x 4bytes = 16)

Saying that, for your simple function I wouldn''t expect a big performance gain over VB, it may even be slower due to DLL calling overhead.

It doesn''t work for me, e-mail me the source to the dll, the vb and the compiled versions thanx.

e-mail at "nuke_bot_5d@yahoo.ca"

OK, I''ve sent you a mail with an Visual C++ example in which I''ve put your function in a C file.

If you''re still having problems it may be because you are using a C++ file rather than C file, which has different name mangling, or some other Borland related DLL making issue, in which case I would recommend finding and checking out the Borland newsgroups.