描述:
#ifndef _INTTABLE_H
#define _INTTABLE_H
typedef HRESULT (STDAPICALLTYPE *INTERFACE_FINDER)(void *pThis, DWORD dwData, REFIID riid, void **ppv);
#define ENTRY_IS_OFFSET INTERFACE_FINDER(-1)
// basic table layout
typedef struct _INTERFACE_ENTRY
{
const IID * pIID; // the IID to match
INTERFACE_FINDER pfnFinder; // finder function
long dwData; // aux data for finder function
} INTERFACE_ENTRY;
// the routine that implements QueryInterface basd on the table
EXTERN_C HRESULT STDAPICALLTYPE InterfaceTableQueryInterface(void *pThis, const INTERFACE_ENTRY *pTable, REFIID riid, void **ppv);
#define BASE_OFFSET(ClassName, BaseName) \
(DWORD(static_cast<BaseName*>(reinterpret_cast<ClassName*>(0x10000000))) - 0x10000000)
#define COMPOSITE_OFFSET(ClassName, BaseName, MemberType, MemberName) \
(DWORD(static_cast<BaseName*>(reinterpret_cast<MemberType*>(0x10000000 + offsetof(ClassName, MemberName)))) - 0x10000000)
#define BEGIN_INTERFACE_TABLE(ClassName) \
typedef ClassName _InterfaceTableClassName;\
static const INTERFACE_ENTRY *GetInterfaceTable(void) \
{\
static const INTERFACE_ENTRY table[] = {\
#define INTERFACE_TABLE_ENTRY(piid, pfn, dwData) \
{ piid, pfn, dwData },
#define IMPLEMENTS_INTERFACE(ItfName) \
{ &IID_##ItfName, ENTRY_IS_OFFSET, BASE_OFFSET(_InterfaceTableClassName, ItfName) },
#define IMPLEMENTS_INTERFACE_AS(RequestedItfName, BaseClassName) \
{ &IID_##RequestedItfName, ENTRY_IS_OFFSET , BASE_OFFSET(_InterfaceTableClassName, BaseClassName)},
#define IMPLEMENTS_INTERFACE_WITH_COMPOSITE(RequestedItfName, DataMemberType, DataMemberName) \
{ &IID_##RequestedItfName, ENTRY_IS_OFFSET , COMPOSITE_OFFSET(_InterfaceTableClassName, RequestedItfName, DataMemberType, DataMemberName) },
#define END_INTERFACE_TABLE() \
{ 0, 0, 0 }\
};\
return table;\
}
#endif
其中 #define ENTRY_IS_OFFSET INTERFACE_FINDER(-1)，这一句该如何理解？