在窗口 7 中移植 32 位到 64 位 MFC 应用程序

Question

I am porting 32-bit application to 64-bit which is built in VC++.net 2003 . I have built this application in VS2010 sp1 successfully in 32-bit and 64-bit platform. But I am facing application crash issues in 64-bit platform(x64) application but not in 32-bit platform(win32) . Crashing is happening at belowcode line

char *pSls = (char*)SendMessage( ::GetParent( ::GetParent( GetParen() ) ),
                                              m_uMessageID,
                                              L_SOM_CHANNEL, nChannel );

In win32 *pSls get data in it but in 64-bit , Expression doesn't evaluate. I have observed return type of SendMessage is LRESULT which is a LONG_PTR and LONG_PTR is long in Win32 and _int64 in 64-bit platform. Could anyone please help to resolve issue?

Actual error which is displaiying: Expression: !IsBadReadPtr((const void )(pszString), sizeof( (pszString)))

Please find more code:

int CMNEditInputTab::GetChanIndx( const int nChannel )
{
   MEMBERASSERT();
   char *pSls = (char *)SendMessage( ::GetParent( ::GetParent( GetParent() ) ),
                                              m_uMessageID,
                                              L_SOM_CHANNEL, nChannel );

   if ( *pSls == NULL )
      return 0;

   int nIndex = GetSignalList().FindString( -1, pSls );

   if ( nIndex != LB_ERR )
      return nIndex;

   return 0;
}
int SN_ListBox::FindString( int nStartIndex, LPCTSTR pszString )
{
   MEMBERASSERT();
   RPTRASSERT(pszString);

   SN_REQUIRES_HWND( SN_ListBox::FindString );

   if ( m_hWnd )
      return ListBox_FindString(m_hWnd, nStartIndex, pszString);
   else
      return 0;
}
void MDCDBG_assert(char *pszExp, char *pszFile, int nLine)
{
#ifdef _DEBUG
   MDCDBG_Initialize();
#ifndef _WIN32_WCE
   int nResponse = _CrtDbgReport(_CRT_ASSERT, pszFile, nLine, NULL, "%s", pszExp);
   if (nResponse == 1)
      _CrtDbgBreak();
#endif

#endif
}

In dbgrpt.c file:

_CRTIMP int __cdecl _CrtDbgReportT(
        int nRptType,
        const TCHAR * szFile,
        int nLine,
        const TCHAR * szModule,
        const TCHAR * szFormat,
        ...
        )
{
    int retval;
    va_list arglist;

    va_start(arglist,szFormat);

    retval = _CrtDbgReportTV(nRptType, szFile, nLine, szModule, szFormat, arglist);//Fails here

    va_end(arglist);

    return retval;
}

Observation: *pSls is not getting data in x64 mode but this variable gets data in win32 mode

Answer 1

There's not enough information to determine the cause. If I'm allowed to speculate, I have seen issues like this before. It looks like the return of your SendMessage() returns a LPCTSTR?

My hunch... You have some string...

LPCTSTR lpszRet  = "abcdef"; // ignore error that this string might be on the stack
return (DWORD) lpszRet; // DWORD, or LONG, etc..., but error is here with pointer truncation

instead use,

return (DWORD_PTR) lpszRet; // or LONG_PTR, etc  ... pointer not truncated