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)``.
A GtkTreeIterCompareFunc should return a negative integer, zero, or a positive integer if
asorts beforeb,asorts withb,orasorts afterbrespectively.If two iters compare as equal, their order in the sorted model is undefined. In order to ensure that the
GtkTreeSortablebehaves as expected, the GtkTreeIterCompareFunc must define a partial order on the model, i.e. it must be reflexive, antisymmetric and transitive.For example, if
modelis a product catalogue, then a compare function for the “price” column could be one which returnsprice_of(a)- price_of(b)``.