delphi - Delphi：使用指针函数

Question

我是 delphi 的新手，我在 delphi 中开发的程序与在 C++ 中开发的 dll 一起工作，我需要使用抛出访问冲突地址异常的指针函数，经过多次测试，我不知道如何解决它。

这是delphi中指针函数的定义，从头文件c ++开始翻译

type
  TMICRCallback   = function: Integer of Object;  stdcall;
  TStatusCallback = function(dwParam: Cardinal): Integer of Object; stdcall;

  type
   TBiMICRSetReadBackFunction =
      function(const nHande:        Integer;
               pMicrCB:             TMICRCallback;
               var pReadBuffSize:    Byte;
               var readCharBuff:     Byte;
               var pStatus:          Byte;
               var pDetail:          Byte
      ): Integer; stdcall;
var
   BiMICRSetReadBackFunction: TBiMICRSetReadBackFunction;

type
   TBiMICRSetReadBackFunction =
      function(const nHande:        Integer;
               pMicrCB:             TMICRCallback;
               var pReadBuffSize:    Byte;
               var readCharBuff:     Byte;
               var pStatus:          Byte;
               var pDetail:          Byte
      ): Integer; stdcall;
var
   BiMICRSetReadBackFunction: TBiMICRSetReadBackFunction;

---

这是调用指针函数的代码

type
  function CBMICRRead : Integer; stdcall;
  function CBMICRStatus(dwStatus: LongWord) : Integer;  stdcall;


  Respuesta      : TMICRCallback;
  Estado         : TStatusCallback;

  BiSetStatusBackFunction(m_hApi, Estado);

 BiMICRSetReadBackFunction (m_hApi,
                                    Respuesta,
                                    m_MICRReadBuffSize,
                                    m_MICRReadBuff[0],
                                    m_MICRReadStatus,
                                    m_MICRReadStDetail); 

---

这是接口的 C++ 端：

typedef int (CALLBACK* MICRCallback)(void);
typedef int (CALLBACK* StatusCallback)(DWORD);


int WINAPI BiSetStatusBackFunction(int  nHandle,
                               int (CALLBACK *pStatusCB)(DWORD dwStatus));

int WINAPI BiMICRSetReadBackFunction(int    nHandle, 
                                     int    (CALLBACK *pMicrCB)(void),
                                     LPBYTE pReadBuffSize,   
                                     LPBYTE readCharBuff,    
                                     LPBYTE pStatus,         
                                     LPBYTE pDetail);        

Answer 1

您必须避免Object从/向 DLL 函数调用结果传递参数。

TMICRCallback   = function: Integer;  stdcall;
TStatusCallback = function(dwParam: Cardinal): Integer; stdcall;