“访问冲突读取位置0x0000000a。”在C ++中

Question

我试图从DLL调用一些nio函数，但不断获取Access违规读取位置错误。这是我的代码。

这些是我想要调用的函数。

 typedef void ( *nio_read)(OUT IOSTAT  *pIoStat,
         IN OUT       IOVSPEC *pIov, 
               IN OUT       EGUREC  *pEgu, 
         IN OUT       IODATA  *pIoData );
 typedef void(*nio_paddr)(OUT IOSTAT *pIoStat, IN OUT IOVSPEC *pIov, 
        IN OUT EGUREC *pEgu, IN char *pszBuff);
 typedef void(*nio_tick_enable)(IOSTAT *pIoStat, IOVSPEC *pIov);
 typedef void(*nio_tick)(short int amount);

这是主要功能

 int main(void)
 {
    nio_read _nio_read;
    nio_tick _nio_tick;
    nio_tick_enable _nio_tick_enable;
    nio_paddr _nio_paddr;
    IOSTAT  *pIoStat = (IOSTAT *)malloc(sizeof(IOSTAT));
    memset(pIoStat,0, sizeof(IOSTAT));

    IOVSPEC *pIov = (IOVSPEC *)malloc(sizeof(IOVSPEC));
    memset(pIov,0,sizeof(IOVSPEC));
    EGUREC  *pEgu =  (EGUREC *)malloc(sizeof(EGUREC));
    memset(pEgu,0,sizeof(EGUREC));
    IODATA  *pIoData = (IODATA *)malloc(sizeof(IODATA));
    memset(pIoData,0,sizeof(IODATA));;

          HINSTANCE hInstLibrary = LoadLibrary("J91STSR.dll");


   if( hInstLibrary ) {
    _nio_read=(nio_read)GetProcAddress(hInstLibrary,"nio_read");
    _nio_paddr=(nio_paddr)GetProcAddress(hInstLibrary,"nio_paddr");
    _nio_tick=(nio_tick)GetProcAddress(hInstLibrary,"nio_tick");
    _nio_tick_enable=(nio_tick_enable)GetProcAddress(hInstLibrary,"nio_tick_enable");
    printf("testttt \n");
    }


if(_nio_read){
    (_nio_read)(pIoStat, pIov,pEgu,pIoData);

  }

  if( hInstLibrary ) {
    FreeLibrary(hInstLibrary );
  }
 }

我在此行收到错误

 (_nio_read)(pIoStat, pIov,pEgu,pIoData);

我还是c ++的新手，我似乎无法弄清问题是什么。