VarAdd, VarSub, VarAnd, VarOr functions don't support BYREF VarType

Question

When I call VarAdd, VarSub, VarAnd, VarOr and similar functions to handle VARIANTs, I have noticed, that indirect VARIANTs are not working.

In your online help you say (i.e. VarAnd)

"...performs a bitwise And operation between two variants of any integral type".

So if (pvarLeft->vt & VT_BYREF) or (pvarRight->vt & VT_BYREF) (i.e. VT_BYREF | VT_I4), pVar->plVal is indeed a pointer to a 4 byte memory block.

HRESULT will throw an error with these Variants.

Why have you stopped here providing the functionality, when you are providing VariantCopyInd, which is supporting VT_BYREF?? It is making a lot of additional code to check for every use of these functions, if there is a VT_BYREF in one of input, and copy the by-refed Variant to a direct Variant and use the function after. Much overhead, ineffective as well.

HRESULT VarAnd(
  [in]  LPVARIANT pvarLeft,
  [in]  LPVARIANT pvarRight,
  [out] LPVARIANT pvarResult
)

Answer 1

After explaining the problem, you see here my complete solution of adding two variants with VT_BYREF support. You need two more VARIANTS in bad case.

It would be nice to get a smart solution of MS for Add, Sub etc., i.e. by declaring
VarAddInd(LPVARIANT, LPVARIANT, LPVARIANT)

As far as you can see in this code snippet, support for VT_I1, VT_UI2, VT_UI4, VT_UI8 and VT_I8 is missing as well.

MS has stopped in the middle to support VB6 classic only.

TCEOLEHELP_DLLEXPORT long __stdcall VariantAdd(LPVARIANT VL, LPVARIANT VR, LPVARIANT VResult) {
    LPVARIANT PL; LPVARIANT PR; long ret;
    if (VarHelpL == NULL) VarHelpL = VariantNew();
    if (VarHelpR == NULL) VarHelpR = VariantNew();
 
    short vt = VL->vt;
    if (vt & VT_BYREF) {
        ret = VariantCopyIndPtr(VarHelpL, VL);
        if (ret) return ret;
        PL = VarHelpL;
        vt = vt & 0x3fff;
    }
    else
        PL = VL;

    if (vt == VT_I1 || vt == VT_UI2 || vt == VT_UI4 || vt == VT_UI8 || vt == VT_I8) {
        if (PL == VarHelpL)
            ret = VariantConvertDECIMAL(PL, PL, LOCALE_INVARIANT);
        else {
            ret = VariantConvertDECIMAL(PL, VarHelpL, LOCALE_INVARIANT);
            PL = VarHelpL;
        }
        if (ret) return ret;
    }

    vt = VR->vt;
    if (vt & VT_BYREF) {
        ret = VariantCopyIndPtr(VarHelpR, VR);
        if (ret) return ret;
        PR = VarHelpR;
        vt = vt & 0x3fff;
    }
    else
        PR = VR;

    if (vt == VT_I1 || vt == VT_UI2 || vt == VT_UI4 || vt == VT_UI8 || vt == VT_I8) {
        if (PR == VarHelpR)
            ret = VariantConvertDECIMAL(PR, PR, LOCALE_INVARIANT);
        else {
            ret = VariantConvertDECIMAL(PR, VarHelpR, LOCALE_INVARIANT);
            PR = VarHelpR;
        }
        if (ret) return ret;
    }

    ret = VarAdd(PL, PR, VResult);
    if (PL == VarHelpL) if (VarHelpL) VariantClear(VarHelpL);
    if (PR == VarHelpR) if (VarHelpR) VariantClear(VarHelpR);
    return ret;
}