gtk:icon-view-columns (object)

object -- a gtk:icon-view widget
columns -- an integer for the number of columns

The accessor for the columns slot of the gtk:icon-view class gets or sets the number of the columns in which the items should be displayed. If columns is -1, the number of columns will be chosen automatically to fill the available area. The gtk:icon-view implementation is deprecated since 4.10. Use the gtk:grid-view implementation instead.