panel(3x)                                                            panel(3x)
       panel - panel stack extension for curses
       #include <panel.h>
       cc [flags] sourcefiles -lpanel -lncurses
       PANEL *new_panel(WINDOW *win);
       int bottom_panel(PANEL *pan);
       int top_panel(PANEL *pan);
       int show_panel(PANEL *pan);
       void update_panels(void);
       int hide_panel(PANEL *pan);
       WINDOW *panel_window(const PANEL *pan);
       int replace_panel(PANEL *pan, WINDOW *window);
       int move_panel(PANEL *pan, int starty, int startx);
       int panel_hidden(const PANEL *pan);
       PANEL *panel_above(const PANEL *pan);
       PANEL *panel_below(const PANEL *pan);
       int set_panel_userptr(PANEL *pan, const void *ptr);
       const void *panel_userptr(const PANEL *pan);
       int del_panel(PANEL *pan);
       /* ncurses-extensions */
       PANEL *ground_panel(SCREEN *sp);
       PANEL *ceiling_panel(SCREEN *sp);
       Panels  are  curses(3x) windows with the added feature of depth.  Panel
       functions allow the use  of  stacked  windows  and  ensure  the  proper
       portions  of  each  window  and  the curses stdscr window are hidden or
       displayed when panels are added, moved, modified or removed.   The  set
       of  currently visible panels is the stack of panels.  The stdscr window
       is beneath all panels, and is not considered part of the stack.
       A window is associated with every panel.  The panel routines enable you
       to  create, move, hide, and show panels, as well as position a panel at
       any desired location in the stack.
       Panel routines are a functional layer added to  curses(3x),  make  only
       high-level curses calls, and work anywhere terminfo curses does.
       bottom_panel(pan) puts panel pan at the bottom of all panels.
       ceiling_panel(sp) acts like panel_below(NULL), for the given SCREEN sp.
       del_panel(pan)  removes  the  given  panel  pan  from  the   stack  and
       deallocates the PANEL structure (but not its associated window).
       ground_panel(sp) acts like panel_above(NULL), for the given SCREEN sp.
       hide_panel(pan) removes the given panel pan from the  panel  stack  and
       thus  hides  it  from  view.   The  PANEL structure is not lost, merely
       removed from the stack.
       move_panel(pan,starty,startx) moves the given  panel  pan's  window  so
       that  its  upper-left  corner is at starty, startx.  It does not change
       the position of the panel in the stack.  Be sure to use this  function,
       not mvwin(3x), to move a panel window.
       new_panel(win)  allocates   a  PANEL structure, associates it with win,
       places the panel on the top of the stack (causes  it to  be   displayed
       above any other panel) and returns a pointer to the new panel.
       panel_above(pan)  returns  a  pointer  to  the panel above pan.  If the
       panel argument is (PANEL *)0, it returns a pointer to the bottom  panel
       in the stack.
       panel_below(pan) returns a pointer to the panel just below pan.  If the
       panel argument is (PANEL *)0, it returns a pointer to the top panel  in
       the stack.
       panel_hidden(pan)  returns TRUE if the panel pan is in the panel stack,
       FALSE if it is not.  If the panel is a null pointer, return ERR.
       panel_userptr(pan) returns the user pointer for a given panel pan.
       panel_window(pan) returns a pointer to the window of  the  given  panel
       pan.
       replace_panel(pan,window) replaces the current window of panel pan with
       window This is useful, for example if you want to resize a  panel.   In
       ncurses,  you  can  call replace_panel to resize a panel using a window
       resized with wresize(3x).  It does not change the position of the panel
       in the stack.
       set_panel_userptr(pan,ptr) sets the panel's user pointer.
       show_panel(pan)  makes  a  hidden panel visible by placing it on top of
       the panels in the panel stack.  See COMPATIBILITY below.
       top_panel(pan) puts the given visible panel pan on top of all panels in
       the stack.  See COMPATIBILITY below.
       update_panels()  refreshes  the virtual screen to reflect the relations
       between the panels in the stack, but  does  not  call  doupdate(3x)  to
       refresh the physical screen.  Use this function and not wrefresh(3x) or
       wnoutrefresh(3x).
       update_panels may be called more than once before a call  to  doupdate,
       but  doupdate  is  the  function  responsible for updating the physical
       screen.
       Each routine that returns a pointer returns NULL if  an  error  occurs.
       Each  routine  that  returns  an  int  value  returns OK if it executes
       successfully and ERR if not.
       Except as noted, the pan and window parameters must  be  non-null.   If
       those are null, an error is returned.
       The  move_panel  function  uses  mvwin(3x), and will return an error if
       mvwin returns an error.
       Reasonable care has been taken  to   ensure   compatibility  with   the
       native   panel  facility introduced in System V (inspection of the SVr4
       manual pages suggests the programming  interface  is  unchanged).   The
       PANEL   data  structures  are  merely   similar.   The   programmer  is
       cautioned not to directly use PANEL fields.
       The  functions  show_panel  and  top_panel  are   identical   in   this
       implementation,  and work equally well with displayed or hidden panels.
       In the native System  V  implementation,  show_panel  is  intended  for
       making  a  hidden panel visible (at the top of the stack) and top_panel
       is intended for making an already-visible panel move to the top of  the
       stack.   You  are  cautioned  to  use  the  correct  function to ensure
       compatibility with native panel libraries.
       In your library list, libpanel.a should be  before  libncurses.a;  that
       is, you should say "-lpanel -lncurses", not the other way around (which
       would give a link-error with static libraries).
       The panel facility was documented in SVr4.2 in Character User Interface
       Programming (UNIX SVR4.2).
       It is not part of X/Open Curses.
       A few implementations exist:
       o   Systems  based  on  SVr4  source  code, e.g., Solaris, provide this
           library.
       o   ncurses (since version 0.6 in 1993) and PDCurses (since version 2.2
           in 1995) provide a panel library whose common ancestor was a public
           domain implementation by Warren Tucker published  in  u386mon  2.20
           (1990).
           According  to  Tucker, the SystemV panel library was first released
           in SVr3.2 (1988), and his implementation  helped  with  a  port  to
           SVr3.1 (1987).
           Several  developers have improved each of these; they are no longer
           the same as Tucker's implementation.
       o   NetBSD 8 (2018) has a panel library  begun  by  Valery  Ushakov  in
           2015.  This is based on the AT&T documentation.
       panel.h interface for the panels library
       libpanel.a the panels library itself
       curses(3x), curs_variables(3x),
       This describes ncurses version 6.3 (patch 20211021).
       Originally   written   by   Warren   Tucker  <wht@n4hgf.mt-park.ga.us>,
       primarily to assist in porting u386mon  to  systems  without  a  native
       panels library.
       Repackaged for ncurses by Zeyd ben-Halim.
       Juergen Pfeifer and Thomas E. Dickey revised/improved the library.
                                                                     panel(3x)