Passing array from unmanaged to managed code

Hi,
I have task I believe many people implemented many times.

The C++ application has to pass array of string to C# dll. To my surprise I have found very little about such stuff on the web.
I am able to pass single string, but when I try to pass SAFEARRAY* everything stops to work.
Please help.
To simplify my code I have a function which just pass array, but doesn’t do anything with it.
If I commented out Safearray from function call, it works and return that “105”.

The problem with SAFEARRAY. Is it possible that dll expects some other format of array?

//dll
public interface IEffDpthClc
{
int SetCtArray(int NN, string[] CtFileArray);
}

public class EffDpthClcClass : IEffDpthClc
{
…..
public int SetCtArray(int NN , string[] CtFileArray)
{
return 105; //just test. if I pass array it doesn't work.
}

…
}
//////////////////////////////
//C++MFC application

HRESULT hr = CoInitialize(NULL);
IEffDpthClcPtr pIEffDpthClc(__uuidof(EffDpthClcClass));
SAFEARRAY *pSA;
SAFEARRAYBOUND aDim[1];
aDim[0].lLbound= 0;
aDim[0].cElements=10;
pSA= SafeArrayCreate(VT_VARIANT,1,aDim);
if (pSA != NULL)

{
ConvertCArrayToSmartArr(pSA );
int z =pIEffDpthClc->SetCtArray(NN, pSA,p);
SafeArrayDestroy(pSA);
}
CoUninitialize();

……
HRESULT CPlan::ConvertCArrayToSmartArr(SAFEARRAY *pSA)
{

USES_CONVERSION;
char buffer[10];
HRESULT hr= S_OK;

long aLong[1];

for (long i= 0; i< NN; i++)
{
VARIANT vOut;
VariantInit(&vOut);
vOut.vt= VT_BSTR
ltoa(i,buffer,10); // convert long to ANSI string value
vOut.bstrVal= ::SysAllocString(A2W(buffer)); aLong[0]= i; // set index value
if (hr= SafeArrayPutElement(pSA, aLong, &vOut))
{ // "correctly" copies VARIANT
VariantClear(&vOut); // release BSTR from memory on error
SafeArrayDestroy(pSA); // does a deep destroy on error
return hr;
}
VariantClear(&vOut); // does a deep destroy of source VARIANT
}

}
Thanks a lot. I have strglled with that stuff almost two workdays. Please help.

Sorry.
My array was not good.
It should be

HRESULT hr= S_OK;

long aLong[1];

for (long i= 0; i< NN; i++)
{
CString cs(pArray->GetAt(i));
BSTR bstr = cs.AllocSysString();
aLong[0]= i; // set index value
if (hr= SafeArrayPutElement(pSA, aLong,bstr))
{
::SysFreeString(bstr);
SafeArrayDestroy(pSA); // does a deep destroy on error
return hr;
}
::SysFreeString(bstr);

} // end iteration

Then it works.