Question

我是delphi的新手，我的程序是在delphi中使用C ++开发的dll开发的，我需要使用指针函数来抛出Access Violation地址的异常，经过多次测试我不知道如何解决它。< / p>

这是delphi中指针函数的定义，从头文件c ++

开始转换

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;

这是一个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);

这是界面的C ++方面：

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DLL函数调用结果传递参数。

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

Delphi：使用指针功能

1 个答案: