“可写”；只读系统变量”；（打包）

// MyAcDbHeader.h
#pragma once
#if defined(_M_IX86)
// code is stricly for 32bit x86
namespace MyAcDbHeader {
        // AutoCAD AcDbHeader typedefs.  Get these from the undecorated names
        typedef Acad::ErrorStatus (CALLBACK* SET_TDD_INDWG) (AcDbDate const &);
        typedef Acad::ErrorStatus (CALLBACK* SET_TDD_USR_TIMER) (AcDbDate const &);
        typedef Acad::ErrorStatus (CALLBACK* SET_TDL_CREATE) (AcDbDate const &);
        typedef Acad::ErrorStatus (CALLBACK* SET_TDL_UPDATE) (AcDbDate const &);
        typedef Acad::ErrorStatus (CALLBACK* SET_TDU_CREATE) (AcDbDate const &);
        typedef Acad::ErrorStatus (CALLBACK* SET_TDU_UPDATE) (AcDbDate const &);
        typedef void * (CALLBACK* SLOW_DB_HEADER) (void);
        //// defined to test different template definitions
        //typedef double (CALLBACK* DIM_SCALE) (void);
        //typedef Acad::ErrorStatus (CALLBACK* GET_DIMSTYLE_CHILE_DATA) (AcRxClass const *, AcDbDimStyleTableRecord * &, AcDbObjectId &);
        // pointers to AutoCAD AcDbHeader function pointers.
        // Before using these function they first need to be initialized by calling
        // InitAcDbHeader, otherwise they are set to NULL and will GPF.
        extern SET_TDD_INDWG setTddInDwg;
        extern SET_TDD_USR_TIMER setTddUsrTimer;
        extern SET_TDL_CREATE setTdlCreate;
        extern SET_TDL_UPDATE setTdlUpdate;
        extern SET_TDU_CREATE setTduCreate;
        extern SET_TDU_UPDATE setTduUpdate;
        extern SLOW_DB_HEADER slowDbHeader;
        extern SLOW_DB_HEADER * pAcDbHeader;
        //// declared to test different template definitions
        //extern DIM_SCALE dimScale;
        //extern GET_DIMSTYLE_CHILE_DATA getDimStyleChildData;
        // InitAcDbHeader, must be called prior to using any other function pointers.
        // Makes call to SetAcDbHeaderInstance before returning.
        void InitAcDbHeader(AcDbObjectId stubId = AcDbObjectId::kNull);
        
        // SetAcDbHeaderInstanceFrom retieves the AcDbHeader from AutoCAD by
        // dereferencing stubId to _thiscall (ecx) prior to calling slowDbHeader.
        // If stubId == AcDbObjectId::kNull then _thiscall (ecx) is set to 0 prior
        // to calling slowDbHeader.
        void SetAcDbHeaderInstanceFrom(AcDbObjectId stubId);
// set 1 byte alignment
#pragma pack(push, 1)
        // define typesafe template for AcDbHeader functions that have
        // no parameters.
        // T is the return type
        // T1 is the type of the callee
        template
        T func(T1 callee)
        {
                _asm mov ecx, pAcDbHeader
                        T rVal = callee();
                return rVal;
        }
        // define typesafe template for AcDbHeader functions that have
        // 1 parameter.
        // T is the return type
        // T1 is the type of the callee
        // T2 is the type for parameter 1
        template
        T func(T1 callee, T2 const & inObj)
        {
                _asm mov ecx, pAcDbHeader
                        T rVal = callee(inObj);
                return rVal;
        }
        // define typesafe template for AcDbHeader functions that have
        // 3 parameters.
        // T is the return type
        // T1 is the type of the callee
        // T2 is the type for parameter 1, T3 for parameter 2, T4 for parameter 3
        template
        T func(T1 callee, T2 const * inPtr, T3 *& refPtr, T4 & outObj)
        {
                _asm mov ecx, pAcDbHeader
                        T rVal = callee(inPtr, refPtr, outObj);
                return rVal;
        }
#pragma pack(pop)
}
#endif

// MyAcDbHeader.cpp
#include 
#include "MyAcDbHeader.h"
namespace MyAcDbHeader {
        #if defined(_M_IX86)
        // code is stricly for 32bit x86
        // Define acad family from 2004 to 2006.  They should all have
        // the same mangled AcDbHeader function names, but needs to be
        // varified and coded accordingly.
        // Calling convention is THISCALL, so register ECX needs to be
        // set properly prior to making function calls.
        #if defined(ARX2004)
                #define ACAD2004_FAMILY 1
        #elif defined(ARX2005)
                #define ACAD2004_FAMILY 1
        #elif defined(ARX2006)
                #define ACAD2004_FAMILY 1
        #endif
        // 2007 through 2009 should also have the same mangled AcDbHeader function names
        // Place family check code here, and Place mangled names in InitAcDbHeader.
        // 2010 32 bit, same as 2007 family.
        // 2010 64 bit, calling convention is FASTCALL, Guessing the _thiscall will need to be placed
        // in RCX, but haven't really looked into it
        // Declare instances of AcDbHeader functions.
        SET_TDD_INDWG setTddInDwg = NULL;
        SET_TDD_USR_TIMER setTddUsrTimer = NULL;
        SET_TDL_CREATE setTdlCreate = NULL;
        SET_TDL_UPDATE setTdlUpdate = NULL;
        SET_TDU_CREATE setTduCreate = NULL;
        SET_TDU_UPDATE setTduUpdate = NULL;
        SLOW_DB_HEADER slowDbHeader = NULL;
        SLOW_DB_HEADER * pAcDbHeader = NULL;
        //// declared to test different template definitions
        //DIM_SCALE dimScale = NULL;
        //GET_DIMSTYLE_CHILE_DATA getDimStyleChildData = NULL;
        void InitAcDbHeader(AcDbObjectId stubId) {
                HMODULE hMod = GetModuleHandle("acdb16.dll");
#ifdef ACAD2004_FAMILY 
                // Get addresses of AcDbHeader functions, using mangled string names.
                setTddInDwg = (SET_TDD_INDWG) GetProcAddress(hMod, "?setTddInDwg@AcDbHeader@@QAE?AW4ErrorStatus@Acad@@ABVAcDbDate@@@Z");
                setTddUsrTimer = (SET_TDD_USR_TIMER) GetProcAddress(hMod, "?setTddUsrTimer@AcDbHeader@@QAE?AW4ErrorStatus@Acad@@ABVAcDbDate@@@Z");
                setTdlCreate = (SET_TDL_CREATE) GetProcAddress(hMod, "?setTdlCreate@AcDbHeader@@QAE?AW4ErrorStatus@Acad@@ABVAcDbDate@@@Z");
                setTdlUpdate = (SET_TDL_UPDATE) GetProcAddress(hMod, "?setTdlUpdate@AcDbHeader@@QAE?AW4ErrorStatus@Acad@@ABVAcDbDate@@@Z");
                setTduCreate = (SET_TDU_CREATE) GetProcAddress(hMod, "?setTduCreate@AcDbHeader@@QAE?AW4ErrorStatus@Acad@@ABVAcDbDate@@@Z");
                setTduUpdate = (SET_TDU_UPDATE) GetProcAddress(hMod, "?setTduUpdate@AcDbHeader@@QAE?AW4ErrorStatus@Acad@@ABVAcDbDate@@@Z");
                slowDbHeader = (SLOW_DB_HEADER) GetProcAddress(hMod, "?slowDbHeader@AcDbStub@@ABEPAVAcDbHeader@@XZ");
                //// a couple extra's to test different template definitions
                //dimScale = (DIM_SCALE) GetProcAddress(hMod, "?dimscale@AcDbHeader@@QBENXZ");
                //getDimStyleChildData = (GET_DIMSTYLE_CHILE_DATA) GetProcAddress(hMod, "?getDimstyleChildData@AcDbHeader@@QBE?AW4ErrorStatus@Acad@@PBVAcRxClass@@AAPAVAcDbDimStyleTableRecord@@AAVAcDbObjectId@@@Z");
#endif
                SetAcDbHeaderInstanceFrom(stubId);
        }
        void SetAcDbHeaderInstanceFrom(AcDbObjectId stubId)
        {
                void * pStub = stubId.isValid() ? (void *&) *stubId : NULL;
                _asm mov ecx, pStub
                _asm call slowDbHeader
                _asm mov pAcDbHeader, eax
        }
        #endif
}

// acrxEntryPoint.cpp
...
...
#include "MyAcDbHeader.h"
...
...
// - navSetDwgDate.setDwgDate command (do not rename)
        static void navSetDwgDatesetDwgDate(void)
        {
                using namespace MyAcDbHeader;
                InitAcDbHeader();
                AcDbDate dt;
                Acad::ErrorStatus es;
                es = func(*setTddInDwg, dt);
                es = func(*setTddUsrTimer, dt);
                es = func(*setTdlCreate, dt);
                es = func(*setTdlUpdate, dt);
                es = func(*setTduCreate, dt);
                es = func(*setTduUpdate, dt);
                // double d = func(*dimScale);
                // AcRxClass * rxClass = NULL; // needs to point to an instance of dimension class descriptor
                // AcDbDimStyleTableRecord * pRcd = NULL; // needs to point to instance of AcDbDimStyleTableRecord
                // AcDbObjectId styleId; // if es == eOk then will == dimension style ID
                // es = func(*getDimStyleChildData, rxClass, pRcd, styleId);
        }