gtk-box-pack-start (box child &key expand fill padding)

box -- a gtk-box container widget
child -- the gtk-widget child widget to be added to box
expand -- true if child is to be given extra space allocated to box
fill -- true if space given to child by the expand option is actually allocated to child, rather than just padding it
padding -- an unsigned integer with extra space in pixels

Adds a child widget to the box, packed with reference to the start of the box. The child widget is packed after any other child widget packed with reference to the start of the box.

The extra space of the expand parameter will be divided evenly between all children that use this option. The default value is true.

The fill parameter has no effect if expand is set to false. A child widget is always allocated the full height of a horizontal box and the full width of a vertical box. This option affects the other dimension. The default value is true.

The padding parameter is the extra space in pixels to put between this child widget and its neighbors, over and above the global amount specified by the spacing property. If the child widget is a widget at one of the reference ends of the box, then padding pixels are also put between the child widget and the reference edge of the box. The default value is 0. In the Lisp binding the expand, fill, and padding arguments are keyword arguments, which have default values.