OPS调用RTDB接口示例

最新推荐文章于 2024-01-24 13:49:45 发布

welleo

最新推荐文章于 2024-01-24 13:49:45 发布

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分类专栏： MS Visual Studio .NET 数据库 C++语言文章标签： struct float 数据库 output function input

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该示例展示了如何使用RTDB_Read接口读取数据库中的点的当前值、量程上限值和下限值。通过创建请求缓冲区，设置点名和项名，然后调用RTDB_Read接口，解析回复缓冲区获取浮点值。

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const int NETERR_OK = 0;
const int INVALIDITEMTYPE = -2;

const int PNAMELENGTH = 12; // 点名长度

const int INAMELENGTH = 2; // 项名长度
struct DB_Read_Request_Head
{
short shPointNum; // 点数
};
struct DB_Read_Request_Body
{
CString strPointName; // 点名
CString strItemName; // 项名
};
struct DB_Read_Reply_Head
{
short shPointNum; // 点数
};
struct DB_Read_Reply_Body
{
short shItemType; // 项类型
short shItemLength; // 项长度
};

// 实时数据库多点多项读接口
int RTDB_Read(char* pRequestBuf, int nRequestBufLen, char* pReplyBuf, int nReplyBufLen,
int nTimedOut = -1);

/*
      Function: RTDB_ReadMultiItemMUMDWrap
    Identifier:
   Description: 读取数据库点的当前值、量程上下限
   Input: strPointName: 点名
    strItemName: 项名
  Output: lpCurVal: 当前值
    lpMU: 量程上限值
    lpMD: 量程下限值
  Return: TRUE: 成功
    FALSE: 失败
  Others:
   Revision: Created by Leo on Aug 20, 2009
*/
BOOL RTDB_ReadMultiItemMUMDWrap(CString strPointName,
          CString strItemName,
          LPVOID lpCurVal,
          LPVOID lpMU,
          LPVOID lpMD
          )
{
BOOL bRetVal = FALSE;

int nRequestBufLen = sizeof(DB_Read_Request_Head) + sizeof(DB_Read_Request_Body);
char* pRequestBuf = new char[nRequestBufLen];
DB_Read_Request_Head* pRequestHead = (DB_Read_Request_Head*)pRequestBuf;
DB_Read_Request_Body* pRequestBody = (DB_Read_Request_Body*)(pRequestHead + 1);
pRequestHead->shPointNum = 3;

// Current Value
memcpy(pRequestBody->strPointName, strPointName, PNAMELENGTH);
memcpy(pRequestBody->strItemName, strItemName, INAMELENGTH);
pRequestBody++;

// MU
memcpy(pRequestBody->strPointName, strPointName, PNAMELENGTH);
memcpy(pRequestBody->strItemName, _T("MU"), INAMELENGTH);
pRequestBody++;

// MD
memcpy(pRequestBody->strPointName, strPointName, PNAMELENGTH);
memcpy(pRequestBody->strItemName, _T("MD"), INAMELENGTH);

// Assume all three values are of float type
int nReplyBufLen = sizeof(DB_Read_Reply_Head) + 3 * (sizeof(DB_Read_Reply_Body) + sizeof(float));
char* pReplyBuf = new char[nReplyBufLen];
DB_Read_Reply_Head* pReplyHead = (DB_Read_Reply_Head*)pReplyBuf;
DB_Read_Reply_Body* pReplyBody = (DB_Read_Reply_Body*)(pReplyHead + 1);

int nRetVal = RTDB_Read(pRequestBuf, nRequestBufLen, pReplyBuf, nReplyBufLen);
if (nRetVal != NETERR_OK)
{
  // Error message goes here...
  bRetVal = FALSE;
}
else
{
  char* pVal = (char*)(pReplyBody + 1);
  if (pReplyBody->shItemType != INVALIDITEMTYPE)
  {
   memcpy(lpCurVal, pVal, sizeof(float));
  }
  pReplyBody = (DB_Read_Reply_Body*)(pVal + pReplyBody->shItemLength);

  pVal = (char*)(pReplyBody + 1);
  if (pReplyBody->shItemType != INVALIDITEMTYPE)
  {
   memcpy(lpMU, pVal, sizeof(float));
  }
  pReplyBody = (DB_Read_Reply_Body*)(pVal + pReplyBody->shItemLength);

  pVal = (char*)(pReplyBody + 1);
  if (pReplyBody->shItemType != INVALIDITEMTYPE)
  {
   memcpy(lpMD, pVal, sizeof(float));
  }

bRetVal = TRUE;
}

// Cleaning up goes here...
delete[] pRequestBuf;
pRequestBuf = NULL;
delete[] pReplyBuf;
pReplyBuf = NULL;

return bRetVal;
}