Question

I have following code to find if row is selected, which is selected and which text is in row of GtkTreeView. Code is in key-release event handler.

char *ntext;
if (gtk_tree_selection_get_selected(treeselen, &modelen ,&iteren))
{
    gtk_tree_model_get(modelen, &iteren, cEng, &ntext, -1);
... etc...

This works ok when my view is not empty. But when list is empty I get “segmentation fault”.
I think that before this is needed to check if GtkTreeView is empty.

How to do that?

Actually, later I find if list is partially filled with clicking on unfilled area segfault happens too. So I need solution for that too.

Answer 1

From your description, it appears when you say GtkTreeView is empty you mean in model (GtkTreeModel which is implemented by GtkListStore or GtkTreeStore associated with your GtkTreeView) the data rows are added but are empty i.e. data is not set. In that case you need to check the value returned by gtk_tree_model_get (assuming cEng is valid otherwise you will get a warning message while running the program). Problem mostly is in ...etc.... Just add a NULL check to ntext before operating on it.

char *ntext;
if (gtk_tree_selection_get_selected(treeselen, &modelen ,&iteren))
{
    gtk_tree_model_get(modelen, &iteren, cEng, &ntext, -1);
    if( ntext == NULL )
    {
       printf("Data is NULL!\n");
       /* Handle this case */
    }
   else
   { 
     .... etc ....
   }
}

This could also be the case in you button-press or release callback as well.
Hope this helps!