Re: array from c++ to vb

From:
"Ben Voigt" <rbv@nospam.nospam>
Newsgroups:
microsoft.public.vc.language
Date:
Tue, 14 Nov 2006 09:20:37 -0600
Message-ID:
<#aPxeBACHHA.4472@TK2MSFTNGP03.phx.gbl>
"Simply_Red" <Simply.Red75@gmail.com> wrote in message
news:1163517093.271271.98900@e3g2000cwe.googlegroups.com...

Hi,

i have a C++ DLL used by a vb program,
how can i create in a c++ function an array and let vb use this
array????
i'm i obliged to use SafeArrays???
i create the safearray, but vb don't see the data.....

Private Declare Function MyCppFunction Lib "Mydll.dll" (ByRef tabl()
As Double) As Boolean

sub test()

....
       Dim matable() As Double
        MyCppFunction matable()


Have you tried both with and without the trailing parenthesis on matable?

It's often worth using IDL for this (use a module declarations so you are
working with exported functions, not coclasses). The IDL compiler will
generate a C++ prototype and a type library, so you won't need a Declare
Function statement at all, just add the type library to project references.

....
end sub

matable is empty

bool __declspec(dllexport) CALLBACK MyCppFunction (LPSAFEARRAY FAR
*saFineContours)

{

SAFEARRAY* psa;
double HUGEP * prData;

SAFEARRAYBOUND rgsabound[1];
rgsabound[0].lLbound = 0;
rgsabound[0].cElements = 2;
       psa = SafeArrayCreate(VT_R8,1,rgsabound);
SafeArrayAccessData(psa, (void HUGEP**)&prData);
prData[0] = 1.5;
prData[1] = 2.6;
prData[2] = 10;
saFineContours = &psa;
SafeArrayUnaccessData(psa);

return true;
}

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