Source code of Windows XP (NT5)
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/*--------------------------------------------------------------------------*
*
* Microsoft Windows
* Copyright (C) Microsoft Corporation, 1992 - 1999
*
* File: variant.h
*
* Contents: Interface file for various VARIANT helper functions
*
* History: 19-Nov-1999 jeffro Created
*
*--------------------------------------------------------------------------*/
#pragma once
#ifndef VARIANT_H_INCLUDED
#define VARIANT_H_INCLUDED
/*+-------------------------------------------------------------------------*
* ConvertByRefVariantToByValue
*
* VBScript will has two syntaxes for calling dispinterfaces:
*
* 1. obj.Method (arg)
* 2. obj.Method arg
*
* The first syntax will pass arg by value, which out dispinterfaces will
* be able to handle. If Method takes a BSTR argument, the VARIANT that
* arrives at Method will be of type VT_BSTR.
*
* The second syntax will pass arg by reference. In this case Method will
* receive a VARIANT of type (VT_VARIANT | VT_BYREF). The VARIANT that is
* referenced will be of type VT_BSTR.
*
* This function will dereference the VARIANT and return the direct pointer
* in pVar. Calling this function on a VARIANT that is not VT_BYREF is
* harmless.
*--------------------------------------------------------------------------*/
inline VARIANT* ConvertByRefVariantToByValue (VARIANT* pVar)
{
while ((pVar != NULL) && (V_VT(pVar) == (VT_VARIANT | VT_BYREF)))
{
pVar = V_VARIANTREF(pVar);
}
return (pVar);
}
/*+-------------------------------------------------------------------------*
* IsOptionalParamMissing
*
* Returns true if an optional argument to an Automation method is left
* blank. This is indicated by a type of VT_ERROR with a value of
* DISP_E_PARAMNOTFOUND.
*
* This should be moved to a header.
*--------------------------------------------------------------------------*/
inline bool IsOptionalParamMissing (const VARIANT& var)
{
return ((V_VT(&var) == VT_ERROR) && (V_ERROR(&var) == DISP_E_PARAMNOTFOUND));
}
#endif /* VARIANT_H_INCLUDED */