Here is a list of all documented class members with links to the class documentation for each member:

Fl_Widget() : Fl_Widget
Fl_Widget_Surface() : Fl_Widget_Surface
Fl_Widget_Tracker() : Fl_Widget_Tracker
Fl_Window() : Fl_Window
Fl_Wizard() : Fl_Wizard
w() : Fl, Fl_Copy_Surface, Fl_Help_Dialog, Fl_Help_Link, Fl_Image, Fl_Rect, Fl_Tree_Item, Fl_Widget
w_to_col() : Fl_Terminal
wait() : Fl
wait_for_expose() : Fl_Window
walk_selection() : Fl_Terminal
warning : Fl
watch_widget_pointer() : Fl
wBitCount : Fl_ICO_Image::IconDirEntry
when() : Fl_Table, Fl_Widget
which() : Fl_Tabs
widget() : Fl_Grid, Fl_Tree_Item, Fl_Widget_Tracker
widgetmarginleft() : Fl_Tree, Fl_Tree_Prefs
width : Fl_Paged_Device::page_format
wih : Fl_Table
window() : Fl_Cairo_State, Fl_Widget
window_menu_style() : Fl_Sys_Menu_Bar
window_menu_style_enum : Fl_Sys_Menu_Bar
wiw : Fl_Table
wix : Fl_Table
wiy : Fl_Table
word_end() : Fl_Input_, Fl_Text_Buffer, Fl_Text_Display
word_start() : Fl_Input_, Fl_Text_Buffer, Fl_Text_Display
wPlanes : Fl_ICO_Image::IconDirEntry
wrap() : Fl_Input_, Fl_Spinner
WRAP_AT_BOUNDS : Fl_Text_Display
WRAP_AT_COLUMN : Fl_Text_Display
WRAP_AT_PIXEL : Fl_Text_Display
wrap_mode() : Fl_Text_Display
WRAP_NONE : Fl_Text_Display
wrap_uses_character() : Fl_Text_Display
wrap_width() : Fl_Tooltip
wrapped_column() : Fl_Text_Display
wrapped_line_counter() : Fl_Text_Display
wrapped_row() : Fl_Text_Display