(gobject:define-genum "GtkSizeRequestMode" size-request-mode
  (:export t
   :type-initializer "gtk_size_request_mode_get_type")
  (:height-for-width 0)
  (:width-for-height 1)
  (:constant-size 2))  

:height-for-width

Prefer height-for-width geometry management.

:width-for-height

Prefer width-for-height geometry management.

:constant-size

Do not trade height-for-width or width-for-height geometry management.