Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!mailrus!cornell!uw-beaver!ubc-cs!kiwi!dssmv2!jaccard
From: jaccard@dssmv2.mpr.ca (Philippe Jaccard)
Newsgroups: comp.windows.x.motif
Subject: Motif List boxes
Message-ID: <2304@kiwi.mpr.ca>
Date: 17 Aug 90 23:23:39 GMT
Sender: news@eric.mpr.ca
Reply-To: jaccard@dssmv2.UUCP (Philippe Jaccard)
Organization: Microtel Pacific Research Ltd., Burnaby, B.C., Canada
Lines: 95


I have an application which wishes to dynamically set the items of a list
upon command.
I've used the  XtSetValues function to set the XmNitems and XmNitemCount
property.
As the number of Items is highly variable, I need to allocate/deallocate
memory each time a Initialize the list contents.
I allocate memory to store the array of Xmstring which contents the
items and I call the XtSetValues to store the Items in the List.
I keep a pointer to this array so I can free it before setting a new
one.
It runs great but the size of my executable grows as long as I work with
the list (memory leak).
Does anybody know what does MOTIF do with this array of XmSrring ?
Does the XmList object make an internal copy ?
How do the XmListAddItem and XmListDeleteItem access the list ?
Is XmListDeleteItem the only way to Free the memory space allocated for
the items ?
.
.
.
Any Ideas people?
Philippe

Here follows part of the code(C++) I wrote to access the XmList.

CreateArrayOfString(DoubleLinkedList* list, int &item_count)
{ // CreateArrayOfString

  XmString* string_array;

  // Get the list's size
  int size = list->GetSize();

  // if the list is empty, just return an empty string.
  if(size<=0)
  { // Create an empty string
    string_array = CreateNong[size+1];
  } // Create an empty string
  else
  { // create the array of string

    string_array = new XmString[size+1];

    list->MoveToHead();
    for(int i=0; i<size; i++)
    { // copy all nodes

      // Get current node
      ListNode* node = list->GetCurrentNode();
      string_array[i] = XmStringCreate((char*)node->GetData(),
			(XmStringCharSet)XmSTRING_DEFAULT_CHARSET);

      // Move the current pointer on the following node
      list->MoveToNext();
    } //  copy all nodes
    string_array[size] = NULL;
  } // create the array of string

  // return the item_count
  item_count = size;

  return string_array;
} //CreateArrayOfString

void
SetListItems(Widget    list,
             XmString* new_string,
             int       element_count)
{ // SetListItems

  Arg      arg[3];

  // Replace it with the new list and set the XmNitemCount.
  int i = 0;
  XtSetArg(arg[i], XmNitems, (XtArgVal)(new_string)); i++;
  XtSetArg(arg[i] ,XmNitemCount, (XtArgVal)element_count); i++;
  XtSetValues(list, arg, i);
} // SetListItems
void

FreeArrayOfString(XmString* string_array, int element_count)
{ // FreeArrayOfString

  int i = 0;

  while(i <=  element_count)
  { // free the string
    XmStringFree(string_array[i]);
    i++;
  } // free the string

  // Deallocate the array of string
  delete string_array;
} // FreeArrayOfString