Re: SAFEARRAY - Don't get it :-(

From:

"Egbert Nierop \(MVP for IIS\)" <egbert_nierop@nospam.invalid>

Newsgroups:

microsoft.public.vc.atl

Date:

Thu, 19 Oct 2006 11:37:02 +0200

Message-ID:

<ey4MeI28GHA.940@TK2MSFTNGP03.phx.gbl>

"Anders Eriksson" <andis59@gmail.com> wrote in message
news:19tflj1p58t6n.dlg@ostling.com...

Hello,

In my client I connect to a server and the server returns a SAFEARRAY of
shorts(VT_I2). I can see this in the debugger. I can see that the values
are correct.

When I try to get the items out of the array then it behaves very
strangely. It takes the integer value as the variant type.

What have I done wrong?

The code:

SAFEARRAY *psa;
long NoOfElements=2;
psa=SafeArrayCreateVector(VT_I2, 0, NoOfElements);

psa = pItemValue[0].vDataValue.parray; // here I get the array from the
// server
long lbound;
HRESULT hr=SafeArrayGetLBound(psa, 1, &lbound);
long ubound;
hr=SafeArrayGetUBound(psa, 1, &ubound);

int i=0;
for(;lbound<=ubound;lbound++)
{
CComVariant val;
hr = SafeArrayGetElement(psa, &lbound, (void *) & val);
m_test[i++] = val.intVal;
}

Although some people would swear on using SafeArrayGetElement, the SafeArray
API has not changed since Windows 2000.

I have a better alternative for you.
SafeArrays are contigous! So you can in theory, just loop through the memory
block.

Note that the sample assumes that this array is only meant for Vector
(contiguous) single dimension arrays, normally, they just are!

short* copy_ShortArray;
hr = SafeArrayAccessData(psa, (void**)&copy_ShortArray);
if (hr == S_OK)
{
ULONG els = psa->rgsabound[0].cElements
while(els-- !=0)
m_test[els] = copy_ShortArray[els];
SafeArrayUnaccessData(psa);

}

// Anders
--