Here are the classes, structs, unions and interfaces with brief descriptions:

CGTK
CGTKAboutDialog
CGTKAccelLabel
CGTKAlignment
CGTKArrow
CGTKAspectFrame
CGTKAssistant
CGTKBin
CGTKBox
CGTKBuilder
CGTKButton
CGTKButtonBox
CGTKCalendar
CGTKCallbackData
CGTKCellView
CGTKCheckButton
CGTKCheckMenuItem
CGTKColorButton
CGTKColorSelection
CGTKColorSelectionDialog
CGTKCombo
CGTKComboBox
CGTKComboBoxText
CGTKContainer
CGTKDialog
CGTKDrawingArea
CGTKEntry
CGTKEventBox
CGTKExpander
CGTKFileChooserButton
CGTKFileChooserDialog
CGTKFileChooserWidget
CGTKFixed
CGTKFontButton
CGTKFontSelection
CGTKFontSelectionDialog
CGTKFrame
CGTKHandleBox
CGTKHBox
CGTKHButtonBox
CGTKHPaned
CGTKHScale
CGTKHScrollbar
CGTKHSeparator
CGTKHSV
CGTKIconView
CGTKImage
CGTKImageMenuItem
CGTKInfoBar
CGTKInvisible
CGTKItem
CGTKLabel
CGTKLayout
CGTKLinkButton
CGTKMenu
CGTKMenuBar
CGTKMenuItem
CGTKMenuShell
CGTKMenuToolButton
CGTKMessageDialog
CGTKMisc
CGTKNotebook
CGTKObject
CGTKOffscreenWindow
CGTKPageSetupUnixDialog
CGTKPaned
CGTKPlug
CGTKProgress
CGTKProgressBar
CGTKRadioButton
CGTKRadioMenuItem
CGTKRadioToolButton
CGTKRange
CGTKRecentChooserDialog
CGTKRecentChooserMenu
CGTKRecentChooserWidget
CGTKScale
CGTKScaleButton
CGTKScrollbar
CGTKScrolledWindow
CGTKSeparator
CGTKSeparatorMenuItem
CGTKSeparatorToolItem
CGTKSignalConnector
CGTKSignalData
CGTKSocket
CGTKSpinButton
CGTKSpinner
CGTKStatusbar
CGTKTable
CGTKTearoffMenuItem
CGTKTextView
CGTKToggleButton
CGTKToggleToolButton
CGTKToolbar
CGTKToolButton
CGTKToolItem
CGTKToolItemGroup
CGTKToolPalette
CGTKTreeView
CGTKVBox
CGTKVButtonBox
CGTKViewport
CGTKVolumeButton
CGTKVPaned
CGTKVScale
CGTKVScrollbar
CGTKVSeparator
CGTKWidget
CGTKWindow
HelloWorld