else        {         SetpDOBegin(&ovs[ovi],1);         SetpDOEnd(&ovs[ovi],0);         SetpType(&ovs[ovi],MULTIFIELD);         SetpValue(&ovs[ovi],ProceduralPrimitiveData(theEnv)->NoParamValue);        }      ovs[ovi].supplementalInfo = slotName;      ovExprs = ovExprs->nextArg->nextArg;      ovs[ovi].next = (ovExprs != NULL) ? &ovs[ovi+1] : NULL;      ovi++;     }   return(ovs);EvaluateOverridesError:   rm(theEnv,(void *) ovs,(sizeof(DATA_OBJECT) * (*ovCnt)));   *error = TRUE;   return(NULL);  }/**********************************************************  NAME         : DeleteSlotOverrideEvaluations  DESCRIPTION  : Deallocates slot override evaluation array  INPUTS       : 1) The data object array                 2) The number of elements  RETURNS      : Nothing useful  SIDE EFFECTS : Deallocates slot override data object                 array for modify- and duplicate- instance  NOTES        : None **********************************************************/static void DeleteSlotOverrideEvaluations(  void *theEnv,  DATA_OBJECT *ovEvals,  int ovCnt)  {   if (ovEvals != NULL)     rm(theEnv,(void *) ovEvals,(sizeof(DATA_OBJECT) * ovCnt));  }/**********************************************************  NAME         : ModifyMsgHandlerSupport  DESCRIPTION  : Support routine for DirectModifyMsgHandler                 and MsgModifyMsgHandler                 Performs a series of slot updates                 directly or with messages  INPUTS       : 1) A data object buffer to hold the result                 2) A flag indicating whether to use                    put- messages or direct placement  RETURNS      : Nothing useful  SIDE EFFECTS : Slots updated (messages sent)  NOTES        : None **********************************************************/static void ModifyMsgHandlerSupport(  void *theEnv,  DATA_OBJECT *result,  int msgpass)  {   DATA_OBJECT *slotOverrides,*newval,temp,junk;   EXPRESSION msgExp;   INSTANCE_TYPE *ins;   INSTANCE_SLOT *insSlot;   result->type = SYMBOL;   result->value = EnvFalseSymbol(theEnv);   if (InstanceData(theEnv)->ObjectModDupMsgValid == FALSE)     {      PrintErrorID(theEnv,"INSMODDP",1,FALSE);      EnvPrintRouter(theEnv,WERROR,"Direct/message-modify message valid only in modify-instance.\n");      SetEvaluationError(theEnv,TRUE);      return;     }   InstanceData(theEnv)->ObjectModDupMsgValid = FALSE;   ins = GetActiveInstance(theEnv);   if (ins->garbage)     {      StaleInstanceAddress(theEnv,"modify-instance",0);      SetEvaluationError(theEnv,TRUE);      return;     }   /* =======================================      Retrieve the slot override data objects      passed from ModifyInstance - the slot      name is stored in the supplementalInfo      field - and the next fields are links      ======================================= */   slotOverrides = (DATA_OBJECT *) GetNthMessageArgument(theEnv,1)->value;   while (slotOverrides != NULL)     {      /* ===========================================================         No evaluation or error checking needs to be done         since this has already been done by EvaluateSlotOverrides()         =========================================================== */      insSlot = FindInstanceSlot(theEnv,ins,(SYMBOL_HN *) slotOverrides->supplementalInfo);      if (insSlot == NULL)        {         SlotExistError(theEnv,ValueToString(slotOverrides->supplementalInfo),"modify-instance");         SetEvaluationError(theEnv,TRUE);         return;        }      if (msgpass)        {         msgExp.type = slotOverrides->type;         if (msgExp.type != MULTIFIELD)           msgExp.value = slotOverrides->value;         else           msgExp.value = (void *) slotOverrides;         msgExp.argList = NULL;         msgExp.nextArg = NULL;         DirectMessage(theEnv,insSlot->desc->overrideMessage,ins,&temp,&msgExp);         if (EvaluationData(theEnv)->EvaluationError ||             ((temp.type == SYMBOL) && (temp.value == EnvFalseSymbol(theEnv))))           return;        }      else        {         if (insSlot->desc->multiple && (slotOverrides->type != MULTIFIELD))           {            temp.type = MULTIFIELD;            temp.value = EnvCreateMultifield(theEnv,1L);            SetDOBegin(temp,1);            SetDOEnd(temp,1);            SetMFType(temp.value,1,(short) slotOverrides->type);            SetMFValue(temp.value,1,slotOverrides->value);            newval = &temp;           }         else           newval = slotOverrides;         if (PutSlotValue(theEnv,ins,insSlot,newval,&junk,"modify-instance") == FALSE)           return;        }      slotOverrides = slotOverrides->next;     }   result->value = EnvTrueSymbol(theEnv);  }/*************************************************************  NAME         : DuplicateMsgHandlerSupport  DESCRIPTION  : Support routine for DirectDuplicateMsgHandler                 and MsgDuplicateMsgHandler                 Performs a series of slot updates                 directly or with messages  INPUTS       : 1) A data object buffer to hold the result                 2) A flag indicating whether to use                    put- messages or direct placement  RETURNS      : Nothing useful  SIDE EFFECTS : Slots updated (messages sent)  NOTES        : None *************************************************************/static void DuplicateMsgHandlerSupport(  void *theEnv,  DATA_OBJECT *result,  int msgpass)  {   INSTANCE_TYPE *srcins,*dstins;   SYMBOL_HN *newName;   DATA_OBJECT *slotOverrides;   EXPRESSION *valArg,msgExp;   long i;   int oldMkInsMsgPass;   INSTANCE_SLOT *dstInsSlot;   DATA_OBJECT temp,junk,*newval;   result->type = SYMBOL;   result->value = EnvFalseSymbol(theEnv);   if (InstanceData(theEnv)->ObjectModDupMsgValid == FALSE)     {      PrintErrorID(theEnv,"INSMODDP",2,FALSE);      EnvPrintRouter(theEnv,WERROR,"Direct/message-duplicate message valid only in duplicate-instance.\n");      SetEvaluationError(theEnv,TRUE);      return;     }   InstanceData(theEnv)->ObjectModDupMsgValid = FALSE;   /* ==================================      Grab the slot override expressions      and determine the source instance      and the name of the new instance      ================================== */   srcins = GetActiveInstance(theEnv);   newName = (SYMBOL_HN *) GetNthMessageArgument(theEnv,1)->value;   slotOverrides = (DATA_OBJECT *) GetNthMessageArgument(theEnv,2)->value;   if (srcins->garbage)     {      StaleInstanceAddress(theEnv,"duplicate-instance",0);      SetEvaluationError(theEnv,TRUE);      return;     }   if (newName == srcins->name)     {      PrintErrorID(theEnv,"INSMODDP",3,FALSE);      EnvPrintRouter(theEnv,WERROR,"Instance copy must have a different name in duplicate-instance.\n");      SetEvaluationError(theEnv,TRUE);      return;     }   /* ==========================================      Create an uninitialized new instance of      the new name (delete old version - if any)      ========================================== */   oldMkInsMsgPass = InstanceData(theEnv)->MkInsMsgPass;   InstanceData(theEnv)->MkInsMsgPass = msgpass;   dstins = BuildInstance(theEnv,newName,srcins->cls,TRUE);   InstanceData(theEnv)->MkInsMsgPass = oldMkInsMsgPass;   if (dstins == NULL)     return;   dstins->busy++;   /* ================================      Place slot overrides directly or      with put- messages      ================================ */   while (slotOverrides != NULL)     {      /* ===========================================================         No evaluation or error checking needs to be done         since this has already been done by EvaluateSlotOverrides()         =========================================================== */      dstInsSlot = FindInstanceSlot(theEnv,dstins,(SYMBOL_HN *) slotOverrides->supplementalInfo);      if (dstInsSlot == NULL)        {         SlotExistError(theEnv,ValueToString(slotOverrides->supplementalInfo),                        "duplicate-instance");         goto DuplicateError;        }      if (msgpass)        {         msgExp.type = slotOverrides->type;         if (msgExp.type != MULTIFIELD)           msgExp.value = slotOverrides->value;         else           msgExp.value = (void *) slotOverrides;         msgExp.argList = NULL;         msgExp.nextArg = NULL;         DirectMessage(theEnv,dstInsSlot->desc->overrideMessage,dstins,&temp,&msgExp);         if (EvaluationData(theEnv)->EvaluationError ||             ((temp.type == SYMBOL) && (temp.value == EnvFalseSymbol(theEnv))))           goto DuplicateError;        }      else        {         if (dstInsSlot->desc->multiple && (slotOverrides->type != MULTIFIELD))           {            temp.type = MULTIFIELD;            temp.value = EnvCreateMultifield(theEnv,1L);            SetDOBegin(temp,1);            SetDOEnd(temp,1);            SetMFType(temp.value,1,(short) slotOverrides->type);            SetMFValue(temp.value,1,slotOverrides->value);            newval = &temp;           }         else           newval = slotOverrides;         if (PutSlotValue(theEnv,dstins,dstInsSlot,newval,&junk,"duplicate-instance") == FALSE)           goto DuplicateError;        }      dstInsSlot->override = TRUE;      slotOverrides = slotOverrides->next;     }   /* =======================================      Copy values from source instance to new      directly or with put- messages      ======================================= */   for (i = 0 ; i < dstins->cls->localInstanceSlotCount ; i++)     {      if (dstins->slots[i].override == FALSE)        {         if (msgpass)           {            temp.type = (unsigned short)  srcins->slots[i].type;            temp.value = srcins->slots[i].value;            if (temp.type == MULTIFIELD)              {               SetDOBegin(temp,1);               SetDOEnd(temp,GetMFLength(temp.value));              }            valArg = ConvertValueToExpression(theEnv,&temp);            DirectMessage(theEnv,dstins->slots[i].desc->overrideMessage,                          dstins,&temp,valArg);            ReturnExpression(theEnv,valArg);            if (EvaluationData(theEnv)->EvaluationError ||                ((temp.type == SYMBOL) && (temp.value == EnvFalseSymbol(theEnv))))              goto DuplicateError;           }         else           {            temp.type = (unsigned short) srcins->slots[i].type;            temp.value = srcins->slots[i].value;            if (srcins->slots[i].type == MULTIFIELD)              {               SetDOBegin(temp,1);               SetDOEnd(temp,GetMFLength(srcins->slots[i].value));              }            if (PutSlotValue(theEnv,dstins,&dstins->slots[i],&temp,&junk,"duplicate-instance")                 == FALSE)              goto DuplicateError;           }        }     }   /* =======================================      Send init message for message-duplicate      ======================================= */   if (msgpass)     {      for (i = 0 ; i < dstins->cls->instanceSlotCount ; i++)        dstins->slotAddresses[i]->override = TRUE;      dstins->initializeInProgress = 1;      DirectMessage(theEnv,MessageHandlerData(theEnv)->INIT_SYMBOL,dstins,result,NULL);     }   dstins->busy--;   if (dstins->garbage)     {      result->type = SYMBOL;      result->value = EnvFalseSymbol(theEnv);      SetEvaluationError(theEnv,TRUE);     }   else     {      result->type = INSTANCE_NAME;      result->value = (void *) GetFullInstanceName(theEnv,dstins);     }   return;DuplicateError:   dstins->busy--;   QuashInstance(theEnv,dstins);   SetEvaluationError(theEnv,TRUE);  }#endif