In an IP developed in C/C++

To register user-defined scalar functions in an IP developed in C/C++:

1. Implement and register INIT_SCALAR as part of your IP. Refer to "Designing and implementing the required IP functions" in the OpenAccess SDK SQL Engine Programmer’s Reference for C/C++ for information on implementing and using the INIT_SCALAR function.

2. In the INIT_SCALAR function, use dam_add_scalar to register each function.

   /*Register it */
   int mem_ip_init_scalar(IP_HDBC hdbc,
   XM_Tree *pMemTree,
   DAM_HSCALAR_LIST pList )
   {
   dam_add_scalar(pMemTree, pList,"INTVAL",1, ip_func_intval,XO_TYPE_INTEGER,1);
   return DAM_SUCCESS;
   }
   
   /* Implementation of INTVAL scalar function
   * out = INTVAL(a) – out is returned same as the input value
   */
   DAM_HVAL ip_func_intval(DAM_HSTMT hstmt, XM_Tree *pMemTree, DAM_HVALEXP_LIST hValExpList)
   {
   char        sFunctionName[]="Intval";
   DAM_HVALEXP hValExp;
   DAM_HVAL    hVal;
   long        *piInputVal;
   long        lVal;
   int         iInputLen;
   int         iRetCode;
   char        sBuf[128];
   /* get the input */
   hValExp = dam_getFirstValExp(hValExpList);
   iRetCode = dam_getValueOfExp(pMemTree, hValExpList, hValExp, XO_TYPE_INTEGER,
   (void **)&piInputVal, &iInputLen);
   if (iRetCode != DAM_SUCCESS) {
   sprintf(sBuf, "Invalid input to scalar function %s().", sFunctionName);
   dam_addError(NULL, hstmt, DAM_ERR_01000, 0, sBuf);
   tm_trace(sqldrv_tmHandle, UL_TM_ERRORS, "%s\n", (sBuf));
   return NULL;
   }
   
   if (iInputLen == XO_NULL_DATA) { /* return NULL */
   hVal = dam_createVal(pMemTree, XO_TYPE_INTEGER, NULL, XO_NULL_DATA);
   return hVal;
   }
   lVal = *piInputVal;
   hVal = dam_createVal(pMemTree, XO_TYPE_INTEGER, &lVal, sizeof(lVal));
   return hVal;
   }
   

3. Optionally, in the INIT_SCALAR function, use dam_add_scalarEx2 to register each function with a qualifier.

   /*Register it */
   int mem_ip_init_scalar(IP_HDBC hdbc,
   XM_Tree *pMemTree,
   DAM_HSCALAR_LIST pList )
   {
   dam_add_scalarEx2(pMemTree, pList,"INTEGER", "ADD",1, ip_func_integer_add,
   XO_TYPE_INTEGER,1);
   dam_add_scalarEx2(pMemTree, pList,"STRING", "ADD",1, ip_func_String_add,
   XO_TYPE_VARCHAR,1);
   return DAM_SUCCESS;
   }