GtkCList::set_selection_mode

void set_selection_mode(GtkSelectionMode mode);

Sets the selection mode for the specified CList. This allows you to set whether only one or more than one item can be selected at a time in the widget. Note that setting the widget's selection mode to one of GTK_SELECTION_BROWSE or GTK_SELECTION_SINGLE will cause all the items in the GtkCList to become deselected.