Outlook add-in integrating Skype

#include "Sdk.h"
#include "VariantUtils.h"

HRESULT
Variant_SetBool(
    VARIANT     *Variant, 
    BOOL        Value
) {
    if(Variant == NULL) {
        return E_POINTER;
    }

    V_VT(Variant)   = VT_BOOL;
    V_BOOL(Variant) = Value ? VARIANT_TRUE : VARIANT_FALSE;

    return S_OK;
}

HRESULT
Variant_SetLong(
    VARIANT     *Variant, 
    LONG        Value
) {
    if(Variant == NULL) {
        return E_POINTER;
    }

    V_VT(Variant) = VT_I4;
    V_I4(Variant) = Value;

    return S_OK;
}

HRESULT
Variant_SetString(
    VARIANT     *Variant, 
    LPCWSTR     Value
) {
    BSTR bstr = NULL;

    if(Variant == NULL) {
        return E_POINTER;
    }
    if(Value == NULL) {
        return E_INVALIDARG;
    }

    bstr = SysAllocString(Value);
    if(bstr == NULL) {
        return E_OUTOFMEMORY;
    }

    V_VT(Variant)   = VT_BSTR;
    V_BSTR(Variant) = bstr;

    return S_OK;
}

HRESULT
Variant_SetDispatch(
    VARIANT     *Variant, 
    IDispatch   *Value
) {
    if(Variant == NULL) {
        return E_POINTER;
    }

    V_VT(Variant) = VT_DISPATCH;
    if(Value == NULL) {
        V_DISPATCH(Variant) = NULL;
    }
    else {
        IDispatch_QueryInterface(Value, 
                                 &IID_IDispatch, 
                                 (void **)&(V_DISPATCH(Variant))
                                );
    }
    return S_OK;
}