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