Function
GtkTreeIterCompareFunc
Declaration
int
TreeIterCompareFunc (
  GtkTreeModel* model,
  GtkTreeIter* a,
  GtkTreeIter* b,
  gpointer user_data
)
Description [src]
A GtkTreeIterCompareFunc should return a negative integer, zero, or a positive
integer if a sorts before b, a sorts with b, or a sorts after b
respectively.
If two iters compare as equal, their order in the sorted model
is undefined. In order to ensure that the GtkTreeSortable behaves as
expected, the GtkTreeIterCompareFunc must define a partial order on
the model, i.e. it must be reflexive, antisymmetric and transitive.
For example, if model is a product catalogue, then a compare function
for the “price” column could be one which returns
price_of(a) - price_of(b).
Parameters
| model | GtkTreeModel | 
| The  | |
| The data is owned by the caller of the function. | |
| a | GtkTreeIter | 
| A  | |
| The data is owned by the caller of the function. | |
| b | GtkTreeIter | 
| Another  | |
| The data is owned by the caller of the function. | |
| user_data | gpointer | 
| Data passed when the compare func is assigned e.g. by gtk_tree_sortable_set_sort_func(). |