--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/window.c	Mon Aug 13 11:28:15 2007 +0200
@@ -0,0 +1,6006 @@
+/* Window creation, deletion and examination for XEmacs.
+   Copyright (C) 1985-1987, 1992-1995 Free Software Foundation, Inc.
+   Copyright (C) 1994, 1995 Board of Trustees, University of Illinois.
+   Copyright (C) 1995, 1996 Ben Wing.
+   Copyright (C) 1996 Chuck Thompson.
+
+This file is part of XEmacs.
+
+XEmacs is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by the
+Free Software Foundation; either version 2, or (at your option) any
+later version.
+
+XEmacs is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with XEmacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.  */
+
+/* Synched up with: FSF 19.30. */
+/* Beginning to diverge significantly. */
+
+/* This file has been Mule-ized. */
+
+#include <config.h>
+#include "lisp.h"
+
+#include "buffer.h"
+#include "faces.h"
+#include "frame.h"
+#include "objects.h"
+#include "glyphs.h"
+#include "redisplay.h"
+#include "window.h"
+#include "elhash.h"
+#include "commands.h"
+#include "gutter.h"
+
+Lisp_Object Qwindowp, Qwindow_live_p, Qwindow_configurationp;
+Lisp_Object Qdisplay_buffer;
+
+#ifdef MEMORY_USAGE_STATS
+Lisp_Object Qface_cache, Qglyph_cache, Qline_start_cache, Qother_redisplay;
+#ifdef HAVE_SCROLLBARS
+Lisp_Object Qscrollbar_instances;
+#endif
+#endif
+
+EXFUN (Fnext_window, 4);
+
+static int window_pixel_width_to_char_width (struct window *w,
+					     int pixel_width,
+					     int include_margins_p);
+static int window_char_width_to_pixel_width (struct window *w,
+					     int char_width,
+					     int include_margins_p);
+static int window_pixel_height_to_char_height (struct window *w,
+					       int pixel_height,
+					       int include_gutters_p);
+static int window_char_height_to_pixel_height (struct window *w,
+					       int char_height,
+					       int include_gutters_p);
+static void change_window_height (struct window *w, int delta, int widthflag,
+                                  int inpixels);
+
+/* Thickness of shadow border around 3d modelines. */
+Lisp_Object Vmodeline_shadow_thickness;
+
+/* Whether vertical dividers are draggable and displayed */
+Lisp_Object Vvertical_divider_always_visible_p;
+
+/* Whether a modeline should be displayed. */
+Lisp_Object Vhas_modeline_p;
+
+/* Thickness of shadow border around vertical dividers. */
+Lisp_Object Vvertical_divider_shadow_thickness;
+
+/* Divider surface width (not counting 3-d borders) */
+Lisp_Object Vvertical_divider_line_width;
+
+/* Spacing between outer egde of divider border and window edge */
+Lisp_Object Vvertical_divider_spacing;
+
+/* How much to scroll by per-line. */
+Lisp_Object Vwindow_pixel_scroll_increment;
+
+/* Scroll if point lands on the bottom line and that line is partially
+   clipped. */
+int scroll_on_clipped_lines;
+
+/* The minibuffer window of the selected frame.
+   Note that you cannot test for minibufferness of an arbitrary window
+   by comparing against this; but you can test for minibufferness of
+   the selected window.  */
+Lisp_Object minibuf_window;
+
+/* Non-nil means it is the window for C-M-v to scroll
+   when the minibuffer is selected.  */
+Lisp_Object Vminibuffer_scroll_window;
+
+/* Non-nil means this is the buffer whose window C-M-v should scroll.  */
+Lisp_Object Vother_window_scroll_buffer;
+
+/* Non-nil means it's the function to call to display temp buffers.  */
+Lisp_Object Vtemp_buffer_show_function;
+
+Lisp_Object Vtemp_buffer_show_hook;
+
+/* If a window gets smaller than either of these, it is removed. */
+int window_min_height;
+int window_min_width;
+
+/* Hook run at end of temp_output_buffer_show.  */
+Lisp_Object Qtemp_buffer_show_hook;
+
+/* Number of lines of continuity in scrolling by screenfuls.  */
+int next_screen_context_lines;
+
+/* List of freed window configurations with 1 - 10 windows. */
+static Lisp_Object Vwindow_configuration_free_list[10];
+
+#define SET_LAST_MODIFIED(w, cache_too)		\
+do {						\
+  (w)->last_modified[CURRENT_DISP] = Qzero;	\
+  (w)->last_modified[DESIRED_DISP] = Qzero;	\
+  (w)->last_modified[CMOTION_DISP] = Qzero;	\
+  if (cache_too)				\
+    (w)->line_cache_last_updated = Qzero;	\
+} while (0)
+
+#define SET_LAST_FACECHANGE(w)			\
+do {						\
+  (w)->last_facechange[CURRENT_DISP] = Qzero;	\
+  (w)->last_facechange[DESIRED_DISP] = Qzero;	\
+  (w)->last_facechange[CMOTION_DISP] = Qzero;	\
+} while (0)
+
+
+#define MARK_DISP_VARIABLE(field)		\
+  mark_object (window->field[CURRENT_DISP]);	\
+  mark_object (window->field[DESIRED_DISP]);	\
+  mark_object (window->field[CMOTION_DISP]);
+
+static Lisp_Object
+mark_window (Lisp_Object obj)
+{
+  struct window *window = XWINDOW (obj);
+  mark_object (window->frame);
+  mark_object (window->mini_p);
+  mark_object (window->next);
+  mark_object (window->prev);
+  mark_object (window->hchild);
+  mark_object (window->vchild);
+  mark_object (window->parent);
+  mark_object (window->buffer);
+  MARK_DISP_VARIABLE (start);
+  MARK_DISP_VARIABLE (pointm);
+  mark_object (window->sb_point);	/* #### move to scrollbar.c? */
+  mark_object (window->use_time);
+  MARK_DISP_VARIABLE (last_modified);
+  MARK_DISP_VARIABLE (last_point);
+  MARK_DISP_VARIABLE (last_start);
+  MARK_DISP_VARIABLE (last_facechange);
+  mark_object (window->line_cache_last_updated);
+  mark_object (window->redisplay_end_trigger);
+  mark_object (window->subwindow_instance_cache);
+
+  mark_face_cachels (window->face_cachels);
+  mark_glyph_cachels (window->glyph_cachels);
+
+#define WINDOW_SLOT(slot, compare) mark_object (window->slot)
+#include "winslots.h"
+
+  return Qnil;
+}
+
+static void
+print_window (Lisp_Object obj, Lisp_Object printcharfun, int escapeflag)
+{
+  char buf[200];
+
+  if (print_readably)
+    error ("printing unreadable object #<window 0x%x>",
+           XWINDOW (obj)->header.uid);
+
+  write_c_string ("#<window", printcharfun);
+  if (!NILP (XWINDOW (obj)->buffer))
+    {
+      Lisp_Object name = XBUFFER (XWINDOW (obj)->buffer)->name;
+      write_c_string (" on ", printcharfun);
+      print_internal (name, printcharfun, 1);
+    }
+  sprintf (buf, " 0x%x>", XWINDOW (obj)->header.uid);
+  write_c_string (buf, printcharfun);
+}
+
+static void
+finalize_window (void *header, int for_disksave)
+{
+  struct window *w = (struct window *) header;
+
+  if (w->line_start_cache)
+    {
+      Dynarr_free (w->line_start_cache);
+      w->line_start_cache = 0;
+    }
+
+  if (w->face_cachels)
+    {
+      int i;
+
+      for (i = 0; i < Dynarr_length (w->face_cachels); i++)
+	{
+	  struct face_cachel *cachel = Dynarr_atp (w->face_cachels, i);
+	  if (cachel->merged_faces)
+	    {
+	      Dynarr_free (cachel->merged_faces);
+	      cachel->merged_faces = 0;
+	    }
+	}
+      Dynarr_free (w->face_cachels);
+      w->face_cachels = 0;
+    }
+
+  if (w->glyph_cachels)
+    {
+      Dynarr_free (w->glyph_cachels);
+      w->glyph_cachels = 0;
+    }
+}
+
+DEFINE_LRECORD_IMPLEMENTATION ("window", window,
+                               mark_window, print_window, finalize_window,
+			       0, 0, 0, struct window);
+
+
+#define INIT_DISP_VARIABLE(field, initialization)	\
+  p->field[CURRENT_DISP] = initialization;		\
+  p->field[DESIRED_DISP] = initialization;		\
+  p->field[CMOTION_DISP] = initialization;
+
+/* We have an implicit assertion that the first two elements (default
+   and modeline faces) are always present in the face_element_cache.
+   Normally redisplay ensures this.  However, it is possible for a
+   window to get created and functions which reference these values
+   called before redisplay works with the window for the first time.
+   All callers of allocate_window should therefore call
+   reset_face_cachels on the created window.  We can't do it
+   here because the window must have its frame pointer set or
+   reset_face_cachels will fail. */
+Lisp_Object
+allocate_window (void)
+{
+  Lisp_Object val;
+  struct window *p = alloc_lcrecord_type (struct window, &lrecord_window);
+
+  zero_lcrecord (p);
+  XSETWINDOW (val, p);
+
+  p->dead = 0;
+  p->frame = Qnil;
+  p->mini_p = Qnil;
+  p->next = Qnil;
+  p->prev = Qnil;
+  p->hchild = Qnil;
+  p->vchild = Qnil;
+  p->parent = Qnil;
+  p->buffer = Qnil;
+  INIT_DISP_VARIABLE (start, Fmake_marker ());
+  INIT_DISP_VARIABLE (pointm, Fmake_marker ());
+  p->sb_point = Fmake_marker ();
+  p->use_time = Qzero;
+  INIT_DISP_VARIABLE (last_modified, Qzero);
+  INIT_DISP_VARIABLE (last_point, Fmake_marker ());
+  INIT_DISP_VARIABLE (last_start, Fmake_marker ());
+  INIT_DISP_VARIABLE (last_facechange, Qzero);
+  p->face_cachels     = Dynarr_new (face_cachel);
+  p->glyph_cachels    = Dynarr_new (glyph_cachel);
+  p->line_start_cache = Dynarr_new (line_start_cache);
+  p->subwindow_instance_cache = make_lisp_hash_table (10,
+						      HASH_TABLE_KEY_WEAK,
+						      HASH_TABLE_EQ);
+  p->line_cache_last_updated = Qzero;
+  INIT_DISP_VARIABLE (last_point_x, 0);
+  INIT_DISP_VARIABLE (last_point_y, 0);
+  INIT_DISP_VARIABLE (window_end_pos, 0);
+  p->redisplay_end_trigger = Qnil;
+
+#define WINDOW_SLOT(slot, compare) p->slot = Qnil
+#include "winslots.h"
+
+  p->windows_changed = 1;
+  p->shadow_thickness_changed = 1;
+
+  return val;
+}
+#undef INIT_DISP_VARIABLE
+
+/*
+ * The redisplay structures used to be stored with each window.  While
+ * they are logically something associated with frames they can't be
+ * stored there with a redisplay which handles variable height lines.
+ * Lines in horizontally split windows might not line up.  So they get
+ * stored with the windows.
+ *
+ * The problem with this is window configurations.  When restoring a
+ * window configuration it now becomes problematic to do an
+ * incremental redisplay.  The solution is to store the redisplay
+ * structures with the frame as they should be but laid out in the
+ * same manner as the window structure.  Thus is born the window
+ * mirror.
+ *
+ * It also becomes a convenient place to stick scrollbar instances
+ * since they extrapolate out to having the same problem described for
+ * the display structures.
+ */
+
+/* Create a new window mirror structure and associated redisplay
+   structs. */
+static struct window_mirror *
+new_window_mirror (struct frame *f)
+{
+  struct window_mirror *t = xnew_and_zero (struct window_mirror);
+
+  t->frame = f;
+
+  t->current_display_lines = Dynarr_new (display_line);
+  t->desired_display_lines = Dynarr_new (display_line);
+  t->buffer = NULL;
+
+#ifdef HAVE_SCROLLBARS
+  t->scrollbar_vertical_instance = NULL;
+  t->scrollbar_horizontal_instance = NULL;
+#endif
+
+  return t;
+}
+
+/* Synchronize the mirror structure with a given window structure.
+   This is normally called from update_frame_window_mirror with a
+   starting window of f->root_window. */
+static struct window_mirror *
+update_mirror_internal (Lisp_Object win, struct window_mirror *mir)
+{
+  if (NILP (win))
+    {
+      if (mir)
+	{
+	  free_window_mirror (mir);
+	  mir = NULL;
+	}
+      return mir;
+    }
+  else
+    if (!mir)
+      mir = new_window_mirror (XFRAME (XWINDOW (win)->frame));
+
+  mir->next   = update_mirror_internal (XWINDOW (win)->next,   mir->next);
+  mir->hchild = update_mirror_internal (XWINDOW (win)->hchild, mir->hchild);
+  mir->vchild = update_mirror_internal (XWINDOW (win)->vchild, mir->vchild);
+
+  /*
+   * If the redisplay structs are not empty and the mirror has
+   * children, then this mirror structure was formerly being used for
+   * display but is no longer.  Reset its current display structs so
+   * that redisplay doesn't accidentally think they are accurate if it
+   * is later used for display purposes once again.  Also, mark the
+   * scrollbar instance as not active.
+   */
+  if (mir->vchild || mir->hchild)
+    {
+      /* The redisplay structures are big.  Leaving them around in
+         non-leaf windows can add up to a lot of wasted space.  So
+         don't do it. */
+      free_display_structs (mir);
+      mir->current_display_lines = Dynarr_new (display_line);
+      mir->desired_display_lines = Dynarr_new (display_line);
+
+#ifdef HAVE_SCROLLBARS
+      update_window_scrollbars (XWINDOW (win), mir, 0, 0);
+#endif
+      mir->buffer = NULL;
+    }
+
+  return mir;
+}
+
+/* Given a window mirror, determine which real window it contains the
+   redisplay structures for. */
+static Lisp_Object
+real_window_internal (Lisp_Object win, struct window_mirror *rmir,
+		      struct window_mirror *mir)
+{
+  for (; !NILP (win) && rmir ; win = XWINDOW (win)->next, rmir = rmir->next)
+    {
+      if (mir == rmir)
+	return win;
+      if (!NILP (XWINDOW (win)->vchild))
+	{
+	  Lisp_Object retval =
+	    real_window_internal (XWINDOW (win)->vchild, rmir->vchild, mir);
+	  if (!NILP (retval))
+	    return retval;
+	}
+      if (!NILP (XWINDOW (win)->hchild))
+	{
+	  Lisp_Object retval =
+	    real_window_internal (XWINDOW (win)->hchild, rmir->hchild, mir);
+	  if (!NILP (retval))
+	    return retval;
+	}
+    }
+
+  return Qnil;
+}
+
+/* Given a real window, find the mirror structure which contains its
+   redisplay structures. */
+static struct window_mirror *
+find_window_mirror_internal (Lisp_Object win, struct window_mirror *rmir,
+			    struct window *w)
+{
+  for (; !NILP (win); win = XWINDOW (win)->next, rmir = rmir->next)
+    {
+      if (w == XWINDOW (win))
+	return rmir;
+
+      if (!NILP (XWINDOW (win)->vchild))
+	{
+	  struct window_mirror *retval =
+	    find_window_mirror_internal (XWINDOW (win)->vchild,
+					 rmir->vchild, w);
+	  if (retval) return retval;
+	}
+
+      if (!NILP (XWINDOW (win)->hchild))
+	{
+	  struct window_mirror *retval =
+	    find_window_mirror_internal (XWINDOW (win)->hchild,
+					 rmir->hchild, w);
+	  if (retval) return retval;
+	}
+    }
+
+  return 0;
+}
+
+/* Update the mirror structure for the given frame. */
+void
+update_frame_window_mirror (struct frame *f)
+{
+  f->root_mirror = update_mirror_internal (f->root_window, f->root_mirror);
+  f->mirror_dirty = 0;
+}
+
+/* Free a given mirror structure along with all of its children as
+   well as their associated display structures. */
+void
+free_window_mirror (struct window_mirror *mir)
+{
+  while (mir)
+    {
+      struct window_mirror *prev = mir;
+      if (mir->hchild) free_window_mirror (mir->hchild);
+      if (mir->vchild) free_window_mirror (mir->vchild);
+#ifdef HAVE_SCROLLBARS
+      release_window_mirror_scrollbars (mir);
+#endif
+      free_display_structs (mir);
+      mir = mir->next;
+      xfree (prev);
+    }
+}
+
+/* Given a mirror structure, return the window it mirrors.  Calls
+   real_window_internal to do most of the work. */
+Lisp_Object
+real_window (struct window_mirror *mir, int no_abort)
+{
+  Lisp_Object retval = real_window_internal (mir->frame->root_window,
+					     mir->frame->root_mirror, mir);
+  if (NILP (retval) && !no_abort)
+    abort ();
+
+  return retval;
+}
+
+/* Given a real window, return its mirror structure.  Calls
+   find_window_mirror_internal to do all of the work. */
+struct window_mirror *
+find_window_mirror (struct window *w)
+{
+  struct frame *f = XFRAME (w->frame);
+  if (f->mirror_dirty)
+    update_frame_window_mirror (f);
+  return find_window_mirror_internal (f->root_window, f->root_mirror, w);
+}
+
+/*****************************************************************************
+ find_window_by_pixel_pos
+
+ Given a pixel position relative to a frame, find the window at that
+ position.
+ ****************************************************************************/
+struct window *
+find_window_by_pixel_pos (int pix_x, int pix_y, Lisp_Object win)
+{
+  if (NILP (win))
+    return 0;
+
+  for (; !NILP (win); win = XWINDOW (win)->next)
+    {
+      struct window *w;
+
+      if (!NILP (XWINDOW (win)->vchild))
+	{
+	  w = find_window_by_pixel_pos (pix_x, pix_y, XWINDOW (win)->vchild);
+	  if (w) return w;
+	}
+      if (!NILP (XWINDOW (win)->hchild))
+	{
+	  w = find_window_by_pixel_pos (pix_x, pix_y, XWINDOW (win)->hchild);
+	  if (w) return w;
+	}
+      w = XWINDOW (win);
+      if (pix_x >= WINDOW_LEFT (w)
+	  && pix_x <= WINDOW_RIGHT (w)
+	  && pix_y >= WINDOW_TOP (w)
+	  && pix_y <= WINDOW_BOTTOM (w))
+	return w;
+    }
+  return NULL;
+}
+
+/* Return a pointer to the display structures for the given window. */
+display_line_dynarr *
+window_display_lines (struct window *w, int which)
+{
+  struct window_mirror *t;
+
+  if (XFRAME (w->frame)->mirror_dirty)
+    update_frame_window_mirror (XFRAME (w->frame));
+  t = find_window_mirror (w);
+  if (!t)
+    abort ();
+
+  if (which == CURRENT_DISP)
+    return t->current_display_lines;
+  else if (which == DESIRED_DISP)
+    return t->desired_display_lines;
+  else if (which == CMOTION_DISP)
+    /* The CMOTION_DISP display lines are global. */
+    return cmotion_display_lines;
+  else
+    abort ();
+
+  return 0;	/* shut up compiler */
+}
+
+struct buffer *
+window_display_buffer (struct window *w)
+{
+  struct window_mirror *t;
+
+  if (XFRAME (w->frame)->mirror_dirty)
+    update_frame_window_mirror (XFRAME (w->frame));
+  t = find_window_mirror (w);
+  if (!t)
+    abort ();
+
+  return t->buffer;
+}
+
+void
+set_window_display_buffer (struct window *w, struct buffer *b)
+{
+  struct window_mirror *t;
+
+  if (XFRAME (w->frame)->mirror_dirty)
+    update_frame_window_mirror (XFRAME (w->frame));
+  t = find_window_mirror (w);
+  if (!t)
+    abort ();
+
+  t->buffer = b;
+}
+
+
+/* Determining a window's position based solely on its pixel
+   positioning doesn't work.  Instead, we do it the intelligent way,
+   by checking its positioning in the window hierarchy. */
+int
+window_is_leftmost (struct window *w)
+{
+  Lisp_Object parent, current_ancestor, window;
+
+  XSETWINDOW (window, w);
+
+  parent = XWINDOW (window)->parent;
+  current_ancestor = window;
+
+  while (!NILP (parent))
+    {
+      if (!NILP (XWINDOW (parent)->hchild) &&
+	  !EQ (XWINDOW (parent)->hchild, current_ancestor))
+	return 0;
+
+      current_ancestor = parent;
+      parent = XWINDOW (parent)->parent;
+    }
+
+  return 1;
+}
+
+int
+window_is_rightmost (struct window *w)
+{
+  Lisp_Object parent, current_ancestor, window;
+
+  XSETWINDOW (window, w);
+
+  parent = XWINDOW (window)->parent;
+  current_ancestor = window;
+
+  while (!NILP (parent))
+    {
+      if (!NILP (XWINDOW (parent)->hchild)
+	  && !NILP (XWINDOW (current_ancestor)->next))
+	return 0;
+
+      current_ancestor = parent;
+      parent = XWINDOW (parent)->parent;
+    }
+
+  return 1;
+}
+
+static int
+window_full_width_p (struct window *w)
+{
+  return window_is_leftmost (w) && window_is_rightmost (w);
+}
+
+int
+window_is_highest (struct window *w)
+{
+  Lisp_Object parent, current_ancestor, window;
+
+  XSETWINDOW (window, w);
+
+  parent = XWINDOW (window)->parent;
+  current_ancestor = window;
+
+  while (!NILP (parent))
+    {
+      if (!NILP (XWINDOW (parent)->vchild) &&
+	  !EQ (XWINDOW (parent)->vchild, current_ancestor))
+	return 0;
+
+      current_ancestor = parent;
+      parent = XWINDOW (parent)->parent;
+    }
+
+  /* This is really to catch the minibuffer but we make it generic in
+     case we ever change things around to let the minibuffer be on top. */
+  if (NILP (XWINDOW (current_ancestor)->prev))
+    return 1;
+  else
+    return 0;
+}
+
+int
+window_is_lowest (struct window *w)
+{
+  Lisp_Object parent, current_ancestor, window;
+
+  XSETWINDOW (window, w);
+
+  parent = XWINDOW (window)->parent;
+  current_ancestor = window;
+
+  while (!NILP (parent))
+    {
+      if (!NILP (XWINDOW (parent)->vchild)
+	  && !NILP (XWINDOW (current_ancestor)->next))
+	return 0;
+
+      current_ancestor = parent;
+      parent = XWINDOW (parent)->parent;
+    }
+
+  return 1;
+}
+
+#if 0 /* not currently used */
+
+static int
+window_full_height_p (struct window *w)
+{
+  return window_is_highest (w) && window_is_lowest (w);
+}
+
+#endif
+
+int
+window_truncation_on (struct window *w)
+{
+    /* Minibuffer windows are never truncated.
+       ### is this the right way ? */
+  if (MINI_WINDOW_P (w))
+    return 0;
+
+  /* Horizontally scrolled windows are truncated. */
+  if (w->hscroll)
+    return 1;
+
+  /* If truncate_partial_width_windows is true and the window is not
+     the full width of the frame it is truncated. */
+  if (truncate_partial_width_windows
+      && !(window_is_leftmost (w) && window_is_rightmost (w)))
+    return 1;
+
+  /* If the window's buffer's value of truncate_lines is non-nil, then
+     the window is truncated. */
+  if (!NILP (XBUFFER (w->buffer)->truncate_lines))
+    return 1;
+
+  return 0;
+}
+
+DEFUN ("window-truncated-p", Fwindow_truncated_p, 0, 1, 0, /*
+Returns Non-Nil iff the window is truncated.
+*/
+       (window))
+{
+  struct window *w = decode_window (window);
+
+  return window_truncation_on (w) ? Qt : Qnil;
+}
+
+
+static int
+have_undivided_common_edge (struct window *w_right, void *closure)
+{
+  struct window *w_left = (struct window *) closure;
+  return (WINDOW_RIGHT (w_left) == WINDOW_LEFT (w_right)
+	  && WINDOW_TOP (w_left) < WINDOW_BOTTOM (w_right)
+	  && WINDOW_TOP (w_right) < WINDOW_BOTTOM (w_left)
+#ifdef HAVE_SCROLLBARS
+	  && (NILP (w_right->scrollbar_on_left_p)
+	      || NILP (w_right->vertical_scrollbar_visible_p)
+	      || ZEROP (w_right->scrollbar_width))
+#endif
+	  );
+}
+
+static int
+window_needs_vertical_divider_1 (struct window *w)
+{
+  /* Never if we're on the right */
+  if (window_is_rightmost (w))
+    return 0;
+
+  /* Always if draggable */
+  if (!NILP (w->vertical_divider_always_visible_p))
+    return 1;
+
+#ifdef HAVE_SCROLLBARS
+  /* Our right scrollbar is enough to separate us at the right */
+  if (NILP (w->scrollbar_on_left_p)
+      && !NILP (w->vertical_scrollbar_visible_p)
+      && !ZEROP (w->scrollbar_width))
+    return 0;
+#endif
+
+  /* Ok. to determine whether we need a divider on the left, we must
+     check that our right neighbor windows have scrollbars on their
+     left sides. We must check all such windows which have common
+     left edge with our window's right edge. */
+  return map_windows (XFRAME (WINDOW_FRAME (w)),
+		      have_undivided_common_edge, (void*)w);
+}
+
+int
+window_needs_vertical_divider (struct window *w)
+{
+  if (!w->need_vertical_divider_valid_p)
+    {
+      w->need_vertical_divider_p =
+	window_needs_vertical_divider_1 (w);
+      w->need_vertical_divider_valid_p = 1;
+    }
+  return w->need_vertical_divider_p;
+}
+
+/* Called from invalidate_vertical_divider_cache_in_frame */
+int
+invalidate_vertical_divider_cache_in_window (struct window *w,
+					     void *u_n_u_s_e_d)
+{
+  w->need_vertical_divider_valid_p = 0;
+  return 0;
+}
+
+/* Calculate width of vertical divider, including its shadows
+   and spacing. The returned value is effectively the distance
+   between adjacent window edges. This function does not check
+   whether a window needs a vertical divider, so the returned
+   value is a "theoretical" one */
+int
+window_divider_width (struct window *w)
+{
+  /* the shadow thickness can be negative. This means that the divider
+     will have a depressed look */
+
+  if (FRAME_WIN_P (XFRAME (WINDOW_FRAME (w))))
+    return
+      XINT (w->vertical_divider_line_width)
+      + 2 * XINT (w->vertical_divider_spacing)
+      + 2 * abs (XINT (w->vertical_divider_shadow_thickness));
+  else
+    return XINT (w->vertical_divider_line_width) == 0 ? 0 : 1;
+}
+
+int
+window_scrollbar_width (struct window *w)
+{
+#ifdef HAVE_SCROLLBARS
+  if (!WINDOW_WIN_P (w)
+      || MINI_WINDOW_P (w)
+      || NILP (w->buffer)
+      || NILP (w->vertical_scrollbar_visible_p))
+    /* #### when does NILP (w->buffer) happen? */
+    return 0;
+
+  return XINT (w->scrollbar_width);
+#else
+  return 0;
+#endif /* HAVE_SCROLLBARS */
+}
+
+/* Horizontal scrollbars are only active on windows with truncation
+   turned on. */
+int
+window_scrollbar_height (struct window *w)
+{
+#ifdef HAVE_SCROLLBARS
+  if (!WINDOW_WIN_P (w)
+      || MINI_WINDOW_P (w)
+      || NILP (w->buffer)
+      || NILP (w->horizontal_scrollbar_visible_p)
+      || !window_truncation_on (w))
+    return 0;
+
+  return XINT (w->scrollbar_height);
+#else
+  return 0;
+#endif /* HAVE_SCROLLBARS */
+}
+
+int
+window_modeline_height (struct window *w)
+{
+  struct frame *f = XFRAME (w->frame);
+  int modeline_height;
+
+  if (MINI_WINDOW_P (w) || NILP (w->buffer))
+    {
+      modeline_height = 0;
+    }
+  else if (!WINDOW_HAS_MODELINE_P (w))
+    {
+      if (window_scrollbar_height (w))
+	modeline_height = 0;
+      else
+	{
+	  modeline_height = FRAMEMETH (f, divider_height, ());
+
+	  if (!EQ (Qzero, w->modeline_shadow_thickness) && FRAME_WIN_P (f))
+	    modeline_height += (2 * MODELINE_SHADOW_THICKNESS (w));
+	}
+    }
+  else
+    {
+      if (noninteractive)
+	modeline_height = 0;
+      else
+	{
+	  display_line_dynarr *dla;
+
+	  /* We don't force a regeneration of the modeline here.
+             Instead it is now a precondition that any function calling
+             this should make sure that one of these structures is
+             up-to-date.  In practice this only affects two internal
+             redisplay functions, regenerate_window and
+             regenerate_window_point_center. */
+	  /* We check DESIRED_DISP because if it is valid it is more
+             up-to-date than CURRENT_DISP.  For calls to this outside
+             of redisplay it doesn't matter which structure we check
+             since there is a redisplay condition that these
+             structures be identical outside of redisplay. */
+	  dla = window_display_lines (w, DESIRED_DISP);
+	  if (dla && Dynarr_length (dla) && Dynarr_atp (dla, 0)->modeline)
+	    modeline_height = (Dynarr_atp (dla, 0)->ascent +
+			       Dynarr_atp (dla, 0)->descent);
+	  else
+	    {
+	      dla = window_display_lines (w, CURRENT_DISP);
+	      if (dla && Dynarr_length (dla) && Dynarr_atp (dla, 0)->modeline)
+		modeline_height = (Dynarr_atp (dla, 0)->ascent +
+				   Dynarr_atp (dla, 0)->descent);
+	      else
+		/* This should be an abort except I'm not yet 100%
+                   confident that it won't ever get hit (though I
+                   haven't been able to trigger it).  It is extremely
+                   unlikely to cause any noticeable problem and even if
+                   it does it will be a minor display glitch. */
+		/* #### Bullshit alert.  It does get hit and it causes
+                   noticeable glitches.  real_current_modeline_height
+                   is a kludge to fix this for 19.14. */
+		modeline_height = real_current_modeline_height (w);
+	    }
+
+	  if (!EQ (Qzero, w->modeline_shadow_thickness) && FRAME_WIN_P (f))
+	    modeline_height += (2 * MODELINE_SHADOW_THICKNESS (w));
+	}
+    }
+
+  return modeline_height;
+}
+
+/*****************************************************************************
+ margin_width_internal
+
+ For a given window, return the width in pixels of the specified margin.
+ ****************************************************************************/
+static int
+margin_width_internal (struct window *w, int left_margin)
+{
+  struct buffer *b;
+  int window_cwidth = window_char_width (w, 1);
+  int margin_cwidth;
+  int font_width;
+  Lisp_Object window;
+
+  /* We might be getting called on a non-leaf. */
+  if (NILP (w->buffer))
+    return 0;
+
+  /* The minibuffer never has margins. */
+  if (MINI_WINDOW_P (w))
+    return 0;
+
+  XSETWINDOW (window, w);
+  b = XBUFFER (w->buffer);
+  margin_cwidth = (left_margin ? XINT (w->left_margin_width) :
+		   XINT (w->right_margin_width));
+
+  default_face_height_and_width (window, 0, &font_width);
+
+  /* The left margin takes precedence over the right margin so we
+     subtract its width from the space available for the right
+     margin. */
+  if (!left_margin)
+    window_cwidth -= XINT (w->left_margin_width);
+
+  /* The margin cannot be wider than the window is.  We allow the
+     value to be bigger since it is possible for the user to enlarge
+     the window such that the left margin value would no longer be too
+     big, but we won't return a value that is larger. */
+  if (margin_cwidth > window_cwidth)
+    margin_cwidth = window_cwidth;
+
+  /* At the user level the margin is always specified in characters.
+     Internally however it is manipulated in terms of pixels. */
+  return margin_cwidth * font_width;
+}
+
+int
+window_left_margin_width (struct window *w)
+{
+  return margin_width_internal (w, 1);
+}
+
+int
+window_right_margin_width (struct window *w)
+{
+  return margin_width_internal (w, 0);
+}
+
+/*****************************************************************************
+ Window Gutters
+
+ The gutters of a window are those areas in the boundary defined by
+ w->pixel_top, w->pixel_left, w->pixel_height and w->pixel_width which
+ do not contain text.  Items which may be in the gutters include
+ scrollbars, toolbars and modelines.  The margin areas are not
+ included.  This is an exception made because redisplay special cases
+ the handling of those areas in many places in such a way that
+ including them in the gutter area would make life difficult.
+
+ The size functions refer to height for the bottom and top gutters and
+ width for the left and right gutters.  The starting position
+ functions refer to the Y coord for bottom and top gutters and the X
+ coord for left and right gutters.  All starting positions are
+ relative to the frame, not the window.
+ ****************************************************************************/
+
+int
+window_top_gutter_height (struct window *w)
+{
+  int gutter = WINDOW_REAL_TOP_GUTTER_BOUNDS (w);
+
+  if (!NILP (w->hchild) || !NILP (w->vchild))
+    return 0;
+
+#ifdef HAVE_SCROLLBARS
+  if (!NILP (w->scrollbar_on_top_p))
+    return window_scrollbar_height (w) + gutter;
+  else
+#endif
+    return gutter;
+}
+
+int
+window_bottom_gutter_height (struct window *w)
+{
+  int gutter = WINDOW_REAL_BOTTOM_GUTTER_BOUNDS (w);
+
+  if (!NILP (w->hchild) || !NILP (w->vchild))
+    return 0;
+
+  gutter += window_modeline_height (w);
+
+#ifdef HAVE_SCROLLBARS
+  if (NILP (w->scrollbar_on_top_p))
+    return window_scrollbar_height (w) + gutter;
+  else
+#endif
+    return gutter;
+}
+
+int
+window_left_gutter_width (struct window *w, int modeline)
+{
+  int gutter = WINDOW_REAL_LEFT_GUTTER_BOUNDS (w);
+
+  if (!NILP (w->hchild) || !NILP (w->vchild))
+    return 0;
+
+#ifdef HAVE_SCROLLBARS
+  if (!modeline && !NILP (w->scrollbar_on_left_p))
+    gutter += window_scrollbar_width (w);
+#endif
+
+  return gutter;
+}
+
+int
+window_right_gutter_width (struct window *w, int modeline)
+{
+  int gutter = WINDOW_REAL_RIGHT_GUTTER_BOUNDS (w);
+
+  if (!NILP (w->hchild) || !NILP (w->vchild))
+    return 0;
+
+#ifdef HAVE_SCROLLBARS
+  if (!modeline && NILP (w->scrollbar_on_left_p))
+    gutter += window_scrollbar_width (w);
+#endif
+
+  if (window_needs_vertical_divider (w))
+    gutter += window_divider_width (w);
+
+  return gutter;
+}
+
+
+DEFUN ("windowp", Fwindowp, 1, 1, 0, /*
+Return t if OBJ is a window.
+*/
+       (obj))
+{
+  return WINDOWP (obj) ? Qt : Qnil;
+}
+
+DEFUN ("window-live-p", Fwindow_live_p, 1, 1, 0, /*
+Return t if OBJ is a window which is currently visible.
+*/
+       (obj))
+{
+  return WINDOWP (obj) && WINDOW_LIVE_P (XWINDOW (obj)) ? Qt : Qnil;
+}
+
+DEFUN ("selected-window", Fselected_window, 0, 1, 0, /*
+Return the window that the cursor now appears in and commands apply to.
+If the optional argument CON-DEV-OR-FRAME is specified and is a frame, return
+the selected window used by that frame.  If CON-DEV-OR-FRAME is a device,
+then the selected frame on that device will be used.  If CON-DEV-OR-FRAME
+is a console, the selected frame on that console's selected device will
+be used.  Otherwise, the selected frame is used.
+*/
+       (con_dev_or_frame))
+{
+  if (NILP (con_dev_or_frame) && NILP (Fselected_device (Qnil)))
+    return Qnil; /* happens at startup */
+
+  {
+    struct frame *f = decode_frame_or_selected (con_dev_or_frame);
+    return FRAME_SELECTED_WINDOW (f);
+  }
+}
+
+DEFUN ("last-nonminibuf-window", Flast_nonminibuf_window, 0, 1, 0, /*
+Return the last selected window that is not a minibuffer window.
+If the optional argument CON-DEV-OR-FRAME is specified and is a frame,
+return the last non-minibuffer window used by that frame.  If
+CON-DEV-OR-FRAME is a device, then the selected frame on that device
+will be used.  If CON-DEV-OR-FRAME is a console, the selected frame on
+that console's selected device will be used.  Otherwise, the selected
+frame is used.
+*/
+       (con_dev_or_frame))
+{
+  if (NILP (con_dev_or_frame) && NILP (Fselected_device (Qnil)))
+    return Qnil; /* happens at startup */
+
+  {
+    struct frame *f = decode_frame_or_selected (con_dev_or_frame);
+    return FRAME_LAST_NONMINIBUF_WINDOW (f);
+  }
+}
+
+DEFUN ("minibuffer-window", Fminibuffer_window, 0, 1, 0, /*
+Return the window used now for minibuffers.
+If the optional argument CON-DEV-OR-FRAME is specified and is a frame, return
+the minibuffer window used by that frame.  If CON-DEV-OR-FRAME is a device,
+then the selected frame on that device will be used.  If CON-DEV-OR-FRAME
+is a console, the selected frame on that console's selected device will
+be used.  Otherwise, the selected frame is used.
+*/
+       (con_dev_or_frame))
+{
+  return FRAME_MINIBUF_WINDOW (decode_frame_or_selected (con_dev_or_frame));
+}
+
+DEFUN ("window-minibuffer-p", Fwindow_minibuffer_p, 1, 1, 0, /*
+Return non-nil if WINDOW is a minibuffer window.
+*/
+       (window))
+{
+  return MINI_WINDOW_P (decode_window (window)) ? Qt : Qnil;
+}
+
+DEFUN ("window-first-hchild", Fwindow_first_hchild, 1, 1, 0, /*
+Return the first horizontal child of WINDOW, or nil.
+*/
+       (window))
+{
+  return decode_window (window)->hchild;
+}
+
+DEFUN ("window-first-vchild", Fwindow_first_vchild, 1, 1, 0, /*
+Return the first vertical child of WINDOW, or nil.
+*/
+       (window))
+{
+  return decode_window (window)->vchild;
+}
+
+DEFUN ("window-next-child", Fwindow_next_child, 1, 1, 0, /*
+Return the next window on the same level as WINDOW, or nil.
+*/
+       (window))
+{
+  return decode_window (window)->next;
+}
+
+DEFUN ("window-previous-child", Fwindow_previous_child, 1, 1, 0, /*
+Return the previous window on the same level as WINDOW, or nil.
+*/
+       (window))
+{
+  return decode_window (window)->prev;
+}
+
+DEFUN ("window-parent", Fwindow_parent, 1, 1, 0, /*
+Return the parent of WINDOW, or nil.
+*/
+       (window))
+{
+  return decode_window (window)->parent;
+}
+
+DEFUN ("window-lowest-p", Fwindow_lowest_p, 1, 1, 0, /*
+Return non-nil if WINDOW is along the bottom of its frame.
+*/
+       (window))
+{
+  return window_is_lowest (decode_window (window)) ? Qt : Qnil;
+}
+
+DEFUN ("window-highest-p", Fwindow_highest_p, 1, 1, 0, /*
+Return non-nil if WINDOW is along the top of its frame.
+*/
+       (window))
+{
+  return window_is_highest (decode_window (window)) ? Qt : Qnil;
+}
+
+DEFUN ("window-leftmost-p", Fwindow_leftmost_p, 1, 1, 0, /*
+Return non-nil if WINDOW is along the left edge of its frame.
+*/
+       (window))
+{
+  return window_is_leftmost (decode_window (window)) ? Qt : Qnil;
+}
+
+DEFUN ("window-rightmost-p", Fwindow_rightmost_p, 1, 1, 0, /*
+Return non-nil if WINDOW is along the right edge of its frame.
+*/
+       (window))
+{
+  return window_is_rightmost (decode_window (window)) ? Qt : Qnil;
+}
+
+DEFUN ("pos-visible-in-window-p", Fpos_visible_in_window_p, 0, 2, 0, /*
+Return t if position POS is currently on the frame in WINDOW.
+Returns nil if that position is scrolled vertically out of view.
+POS defaults to point in WINDOW's buffer; WINDOW, to the selected window.
+*/
+       (pos, window))
+{
+  struct window *w = decode_window (window);
+  Bufpos top = marker_position (w->start[CURRENT_DISP]);
+  Bufpos posint;
+  struct buffer *buf = XBUFFER (w->buffer);
+
+  if (NILP (pos))
+    posint = BUF_PT (buf);
+  else
+    {
+      CHECK_INT_COERCE_MARKER (pos);
+      posint = XINT (pos);
+    }
+
+  if (posint < top || posint > BUF_ZV (buf))
+    return Qnil;
+
+  /* w->start can be out of range.  If it is, do something reasonable.  */
+  if (top < BUF_BEGV (buf) || top > BUF_ZV (buf))
+    return Qnil;
+
+  return point_would_be_visible (w, top, posint) ? Qt : Qnil;
+}
+
+
+struct window *
+decode_window (Lisp_Object window)
+{
+  if (NILP (window))
+    return XWINDOW (Fselected_window (Qnil));
+
+  CHECK_LIVE_WINDOW (window);
+  return XWINDOW (window);
+}
+
+DEFUN ("window-buffer", Fwindow_buffer, 0, 1, 0, /*
+Return the buffer that WINDOW is displaying.
+*/
+       (window))
+{
+  return decode_window (window)->buffer;
+}
+
+DEFUN ("window-frame", Fwindow_frame, 0, 1, 0, /*
+Return the frame that window WINDOW is on.
+*/
+       (window))
+{
+  return decode_window (window)->frame;
+}
+
+DEFUN ("window-height", Fwindow_height, 0, 1, 0, /*
+Return the number of default lines in WINDOW.
+This actually works by dividing the window's pixel height (including
+the modeline and horizontal scrollbar, if any) by the height of the
+default font; therefore, the number of displayed lines will probably
+be different.
+Use `window-height' to get consistent results in geometry calculations.
+Use `window-displayed-height' to get the actual number of lines
+currently displayed in a window.
+*/
+       (window))
+{
+  return make_int (window_char_height (decode_window (window), 1));
+}
+
+DEFUN ("window-displayed-height", Fwindow_displayed_height, 0, 1, 0, /*
+Return the number of lines currently displayed in WINDOW.
+This counts the actual number of lines displayed in WINDOW
+\(as opposed to `window-height').  The modeline and horizontal
+scrollbar do not count as lines.  If there is some blank space
+between the end of the buffer and the end of the window, this
+function pretends that there are lines of text in the default
+font there.
+*/
+     (window))
+{
+  return make_int (window_displayed_height (decode_window (window)));
+}
+
+DEFUN ("window-pixel-height", Fwindow_pixel_height, 0, 1, 0, /*
+Return the height of WINDOW in pixels.  Defaults to current window.
+This includes the window's modeline and horizontal scrollbar (if any).
+*/
+       (window))
+{
+  return make_int (decode_window (window)->pixel_height);
+}
+
+DEFUN ("window-text-area-pixel-height",
+       Fwindow_text_area_pixel_height, 0, 1, 0, /*
+Return the height in pixels of the text-displaying portion of WINDOW.
+Unlike `window-pixel-height', the space occupied by the modeline and
+horizontal scrollbar, if any, is not counted.
+*/
+     (window))
+{
+  struct window *w = decode_window (window);
+
+  return make_int (WINDOW_TEXT_HEIGHT (w));
+}
+
+DEFUN ("window-displayed-text-pixel-height",
+       Fwindow_displayed_text_pixel_height, 0, 2, 0, /*
+Return the height in pixels of the text displayed in WINDOW.
+Unlike `window-text-area-pixel-height', any blank space below the
+end of the buffer is not included.  If optional argument NOCLIPPED
+is non-nil, do not include space occupied by clipped lines.
+*/
+     (window, noclipped))
+{
+  struct window *w;
+  Bufpos start, eobuf;
+  int defheight;
+  int hlimit, height, prev_height = -1;
+  int line;
+  int elt, nelt, i;
+  int needed;
+  line_start_cache_dynarr *cache;
+
+  if (NILP (window))
+    window = Fselected_window (Qnil);
+
+  CHECK_LIVE_WINDOW (window);
+  w = XWINDOW (window);
+
+  start  = marker_position (w->start[CURRENT_DISP]);
+  hlimit = WINDOW_TEXT_HEIGHT (w);
+  eobuf  = BUF_ZV (XBUFFER (w->buffer));
+
+  default_face_height_and_width (window, &defheight, NULL);
+
+  /* guess lines needed in line start cache + a few extra */
+  needed = (hlimit + defheight-1) / defheight + 3;
+
+  while (1) {
+    elt = point_in_line_start_cache (w, start, needed);
+    assert (elt >= 0); /* in the cache */
+
+    cache = w->line_start_cache;
+    nelt  = Dynarr_length (cache);
+
+    height = 0;
+    for (i = elt; i < nelt; i++) {
+      line = Dynarr_atp (cache, i)->height;
+
+      if (height + line > hlimit)
+        return make_int (!NILP (noclipped) ? height : hlimit);
+
+      height += line;
+
+      if (height == hlimit || Dynarr_atp (cache, i)->end >= eobuf)
+        return make_int (height);
+    }
+
+    /* get here => need more cache lines.  try again. */
+    assert(height > prev_height); /* progress? */
+    prev_height = height;
+
+    needed += ((hlimit - height)*(nelt - elt) + height-1)/height + 3;
+  }
+
+  RETURN_NOT_REACHED(make_int (0))        /* shut up compiler */
+}
+
+DEFUN ("window-width", Fwindow_width, 0, 1, 0, /*
+Return the number of display columns in WINDOW.
+This is the width that is usable columns available for text in WINDOW.
+*/
+       (window))
+{
+  return make_int (window_char_width (decode_window (window), 0));
+}
+
+DEFUN ("window-pixel-width", Fwindow_pixel_width, 0, 1, 0, /*
+Return the width of WINDOW in pixels.  Defaults to current window.
+*/
+       (window))
+{
+  return make_int (decode_window (window)->pixel_width);
+}
+
+DEFUN ("window-text-area-pixel-width",
+       Fwindow_text_area_pixel_width, 0, 1, 0, /*
+Return the width in pixels of the text-displaying portion of WINDOW.
+Unlike `window-pixel-width', the space occupied by the vertical
+scrollbar or divider, if any, is not counted.
+*/
+     (window))
+{
+  struct window *w = decode_window (window);
+
+  return make_int (WINDOW_TEXT_WIDTH (w));
+}
+
+DEFUN ("window-hscroll", Fwindow_hscroll, 0, 1, 0, /*
+Return the number of columns by which WINDOW is scrolled from left margin.
+*/
+       (window))
+{
+  return make_int (decode_window (window)->hscroll);
+}
+
+#ifdef MODELINE_IS_SCROLLABLE
+DEFUN ("modeline-hscroll", Fmodeline_hscroll, 0, 1, 0, /*
+Return the number of columns by which WINDOW's modeline is scrolled from
+left margin. If the window has no modeline, return nil.
+*/
+       (window))
+{
+  struct window *w = decode_window (window);
+
+  return (WINDOW_HAS_MODELINE_P (w)) ? make_int (w->modeline_hscroll) : Qnil;
+}
+
+DEFUN ("set-modeline-hscroll", Fset_modeline_hscroll, 2, 2, 0, /*
+Set number of columns WINDOW's modeline is scrolled from left margin to NCOL.
+NCOL should be zero or positive. If NCOL is negative, it will be forced to 0.
+If the window has no modeline, do nothing and return nil.
+*/
+       (window, ncol))
+{
+  struct window *w = decode_window (window);
+
+  if (WINDOW_HAS_MODELINE_P (w))
+    {
+      int ncols;
+      CHECK_INT (ncol);
+      ncols = XINT (ncol);
+      if (ncols < 0) ncols = 0;
+      if (w->modeline_hscroll != ncols)
+	MARK_MODELINE_CHANGED;
+      w->modeline_hscroll = ncols;
+      return ncol;
+    }
+  return Qnil;
+}
+#endif /* MODELINE_IS_SCROLLABLE */
+
+DEFUN ("set-window-hscroll", Fset_window_hscroll, 2, 2, 0, /*
+Set number of columns WINDOW is scrolled from left margin to NCOL.
+NCOL should be zero or positive.
+*/
+       (window, ncol))
+{
+  struct window *w;
+  int ncols;
+
+  CHECK_INT (ncol);
+  ncols = XINT (ncol);
+  if (ncols < 0) ncols = 0;
+  w = decode_window (window);
+  if (w->hscroll != ncols)
+    MARK_CLIP_CHANGED;	/* FSF marks differently but we aren't FSF. */
+  w->hscroll = ncols;
+  return ncol;
+}
+
+#if 0 /* bogus FSF crock */
+
+xxDEFUN ("window-redisplay-end-trigger",
+	 Fwindow_redisplay_end_trigger, 0, 1, 0, /*
+Return WINDOW's redisplay end trigger value.
+See `set-window-redisplay-end-trigger' for more information.
+*/
+	 (window))
+{
+  return decode_window (window)->redisplay_end_trigger;
+}
+
+xxDEFUN ("set-window-redisplay-end-trigger",
+	 Fset_window_redisplay_end_trigger, 2, 2, 0, /*
+Set WINDOW's redisplay end trigger value to VALUE.
+VALUE should be a buffer position (typically a marker) or nil.
+If it is a buffer position, then if redisplay in WINDOW reaches a position
+beyond VALUE, the functions in `redisplay-end-trigger-functions' are called
+with two arguments: WINDOW, and the end trigger value.
+Afterwards the end-trigger value is reset to nil.
+*/
+	 (window, value))
+{
+  return (decode_window (window)->redisplay_end_trigger = value);
+}
+
+#endif /* 0 */
+
+DEFUN ("window-pixel-edges", Fwindow_pixel_edges, 0, 1, 0, /*
+Return a list of the pixel edge coordinates of WINDOW.
+\(LEFT TOP RIGHT BOTTOM), all relative to 0, 0 at top left corner of frame.
+The frame toolbars and menubars are considered to be outside of this area.
+*/
+       (window))
+{
+  struct window *w = decode_window (window);
+  struct frame *f = XFRAME (w->frame);
+
+  int left = w->pixel_left - FRAME_LEFT_BORDER_END (f);
+  int top  = w->pixel_top  - FRAME_TOP_BORDER_END  (f);
+
+  return list4 (make_int (left),
+		make_int (top),
+		make_int (left + w->pixel_width),
+		make_int (top + w->pixel_height));
+}
+
+DEFUN ("window-text-area-pixel-edges",
+       Fwindow_text_area_pixel_edges, 0, 1, 0, /*
+Return a list of the pixel edge coordinates of the text area of WINDOW.
+Returns the list \(LEFT TOP RIGHT BOTTOM), all relative to 0, 0 at the
+top left corner of the window.
+*/
+       (window))
+{
+  struct window *w = decode_window (window);
+
+  int left   = window_left_gutter_width (w, /* modeline = */ 0);
+  int top    = window_top_gutter_height (w);
+  int right  = WINDOW_WIDTH (w) - window_right_gutter_width (w, 0);
+  int bottom = WINDOW_HEIGHT (w) - window_bottom_gutter_height (w);
+
+  return list4 (make_int (left),
+		make_int (top),
+		make_int (right),
+		make_int (bottom));
+}
+
+DEFUN ("window-point", Fwindow_point, 0, 1, 0, /*
+Return current value of point in WINDOW.
+For a nonselected window, this is the value point would have
+if that window were selected.
+
+Note that, when WINDOW is the selected window and its buffer
+is also currently selected, the value returned is the same as (point).
+It would be more strictly correct to return the `top-level' value
+of point, outside of any save-excursion forms.
+But that is hard to define.
+*/
+       (window))
+{
+  struct window *w = decode_window (window);
+
+  /* The special check for current buffer is necessary for this
+     function to work as defined when called within an excursion. */
+  if (w == XWINDOW (Fselected_window (XFRAME (w->frame)->device))
+      && current_buffer == XBUFFER (w->buffer))
+    return Fpoint (Qnil);
+  return Fmarker_position (w->pointm[CURRENT_DISP]);
+}
+
+DEFUN ("window-start", Fwindow_start, 0, 1, 0, /*
+Return position at which display currently starts in WINDOW.
+This is updated by redisplay or by calling `set-window-start'.
+*/
+       (window))
+{
+  return Fmarker_position (decode_window (window)->start[CURRENT_DISP]);
+}
+
+DEFUN ("window-end", Fwindow_end, 0, 2, 0, /*
+Return position at which display currently ends in WINDOW.
+This is updated by redisplay, when it runs to completion.
+Simply changing the buffer text or setting `window-start'
+does not update this value.
+If GUARANTEE is non-nil, then the return value is guaranteed to be
+the value of window-end at the end of the next full redisplay assuming
+nothing else changes in the meantime.  This function is potentially much
+slower with this flag set.
+*/
+       (window, guarantee))
+{
+  struct window *w = decode_window (window);
+
+  if (NILP (guarantee))
+    {
+      Lisp_Object buf;
+      buf = w->buffer;
+      CHECK_BUFFER (buf);
+      return make_int (BUF_Z (XBUFFER (buf)) - w->window_end_pos[CURRENT_DISP]);
+    }
+  else
+    {
+      Bufpos startp = marker_position (w->start[CURRENT_DISP]);
+      return make_int (end_of_last_line (w, startp));
+    }
+}
+
+DEFUN ("set-window-point", Fset_window_point, 2, 2, 0, /*
+Make point value in WINDOW be at position POS in WINDOW's buffer.
+*/
+       (window, pos))
+{
+  struct window *w = decode_window (window);
+
+  CHECK_INT_COERCE_MARKER (pos);
+  if (w == XWINDOW (Fselected_window (Qnil)))
+    Fgoto_char (pos, Qnil);
+  else
+    set_marker_restricted (w->pointm[CURRENT_DISP], pos, w->buffer);
+
+  MARK_POINT_CHANGED;
+  return pos;
+}
+
+DEFUN ("set-window-start", Fset_window_start, 2, 3, 0, /*
+Make display in WINDOW start at position POS in WINDOW's buffer.
+Optional third arg NOFORCE non-nil inhibits next redisplay
+from overriding motion of point in order to display at this exact start.
+*/
+       (window, pos, noforce))
+{
+  struct window *w = decode_window (window);
+
+  CHECK_INT_COERCE_MARKER (pos);
+  set_marker_restricted (w->start[CURRENT_DISP], pos, w->buffer);
+  /* this is not right, but much easier than doing what is right. */
+  /* w->start_at_line_beg = 0; */
+  /* WTF is the above supposed to mean?  GE */
+  w->start_at_line_beg = beginning_of_line_p (XBUFFER (w->buffer),
+					      marker_position (w->start[CURRENT_DISP]));
+  if (NILP (noforce))
+    w->force_start = 1;
+  w->redo_modeline = 1;
+  SET_LAST_MODIFIED (w, 0);
+  SET_LAST_FACECHANGE (w);
+
+  MARK_WINDOWS_CHANGED (w);
+
+  return pos;
+}
+
+DEFUN ("window-dedicated-p", Fwindow_dedicated_p, 1, 1, 0, /*
+Return WINDOW's dedicated object, usually t or nil.
+See also `set-window-dedicated-p'.
+*/
+       (window))
+{
+  return decode_window (window)->dedicated;
+}
+
+DEFUN ("set-window-dedicated-p", Fset_window_dedicated_p, 2, 2, 0, /*
+Control whether WINDOW is dedicated to the buffer it displays.
+If it is dedicated, Emacs will not automatically change
+which buffer appears in it.
+The second argument is the new value for the dedication flag;
+non-nil means yes.
+*/
+       (window, arg))
+{
+  struct window *w = decode_window (window);
+
+  w->dedicated = NILP (arg) ? Qnil : Qt;
+
+  return w->dedicated;
+}
+
+/* FSFmacs has window-display-table here.  We have display table as a
+   specifier. */
+
+
+/* Record info on buffer window w is displaying
+   when it is about to cease to display that buffer.  */
+static void
+unshow_buffer (struct window *w)
+{
+  Lisp_Object buf = w->buffer;
+
+  if (XBUFFER (buf) != XMARKER (w->pointm[CURRENT_DISP])->buffer)
+    abort ();
+
+  /* FSF disables this check, so I'll do it too.  I hope it won't
+     break things.  --ben */
+#if 0
+  if (w == XWINDOW (Fselected_window (Qnil))
+      || ! EQ (buf, XWINDOW (Fselected_window (Qnil))->buffer))
+    /* Do this except when the selected window's buffer
+       is being removed from some other window.  */
+#endif
+    /* last_window_start records the start position that this buffer
+       had in the last window to be disconnected from it.
+       Now that this statement is unconditional,
+       it is possible for the buffer to be displayed in the
+       selected window, while last_window_start reflects another
+       window which was recently showing the same buffer.
+       Some people might say that might be a good thing.  Let's see.  */
+    XBUFFER (buf)->last_window_start =
+      marker_position (w->start[CURRENT_DISP]);
+
+  /* Point in the selected window's buffer
+     is actually stored in that buffer, and the window's pointm isn't used.
+     So don't clobber point in that buffer.  */
+  if (! EQ (buf, XWINDOW (Fselected_window (Qnil))->buffer))
+    {
+      struct buffer *b= XBUFFER (buf);
+      BUF_SET_PT (b, bufpos_clip_to_bounds (BUF_BEGV (b),
+                                     marker_position (w->pointm[CURRENT_DISP]),
+                                     BUF_ZV (b)));
+    }
+}
+
+/* Put REPLACEMENT into the window structure in place of OLD. */
+static void
+replace_window (Lisp_Object old, Lisp_Object replacement)
+{
+  Lisp_Object tem;
+  struct window *o = XWINDOW (old), *p = XWINDOW (replacement);
+
+  /* If OLD is its frame's root_window, then replacement is the new
+     root_window for that frame.  */
+
+  if (EQ (old, FRAME_ROOT_WINDOW (XFRAME (o->frame))))
+    FRAME_ROOT_WINDOW (XFRAME (o->frame)) = replacement;
+
+  WINDOW_LEFT (p) = WINDOW_LEFT (o);
+  WINDOW_TOP (p) = WINDOW_TOP (o);
+  WINDOW_WIDTH (p) = WINDOW_WIDTH (o);
+  WINDOW_HEIGHT (p) = WINDOW_HEIGHT (o);
+
+  p->next = tem = o->next;
+  if (!NILP (tem))
+    XWINDOW (tem)->prev = replacement;
+
+  p->prev = tem = o->prev;
+  if (!NILP (tem))
+    XWINDOW (tem)->next = replacement;
+
+  p->parent = tem = o->parent;
+  if (!NILP (tem))
+    {
+      if (EQ (XWINDOW (tem)->vchild, old))
+	XWINDOW (tem)->vchild = replacement;
+      if (EQ (XWINDOW (tem)->hchild, old))
+	XWINDOW (tem)->hchild = replacement;
+    }
+
+  /* #### Here, if replacement is a vertical combination
+     and so is its new parent, we should make replacement's
+     children be children of that parent instead. */
+}
+
+/* we're deleting W; set the structure of W to indicate this. */
+
+static void
+mark_window_as_deleted (struct window *w)
+{
+  /* In the loop
+     (while t (split-window) (delete-window))
+     we end up with a tree of deleted windows which are all connected
+     through the `next' slot.  This might not seem so bad, as they're
+     deleted, and will presumably be GCed - but if even *one* of those
+     windows is still being pointed to, by the user, or by a window
+     configuration, then *all* of those windows stick around.
+
+     Since the window-configuration code doesn't need any of the
+     pointers to other windows (they are all recreated from the
+     window-config data), we set them all to nil so that we
+     are able to collect more actual garbage.
+   */
+  w->next = Qnil;
+  w->prev = Qnil;
+  w->hchild = Qnil;
+  w->vchild = Qnil;
+  w->parent = Qnil;
+
+  w->dead = 1;
+
+  /* Free the extra data structures attached to windows immediately so
+     they don't sit around consuming excess space.  They will be
+     reinitialized by the window-configuration code as necessary. */
+  finalize_window ((void *) w, 0);
+}
+
+DEFUN ("delete-window", Fdelete_window, 0, 2, "", /*
+Remove WINDOW from the display.  Default is selected window.
+If window is the only one on the frame, the frame is destroyed.
+Normally, you cannot delete the last non-minibuffer-only frame (you must
+use `save-buffers-kill-emacs' or `kill-emacs').  However, if optional
+second argument FORCE is non-nil, you can delete the last frame. (This
+will automatically call `save-buffers-kill-emacs'.)
+*/
+       (window, force))
+{
+  /* This function can GC if this is the only window in the frame */
+  struct window *w;
+  Lisp_Object parent;
+  struct window *par;
+  Lisp_Object frame;
+  struct frame *f;
+  struct device *d;
+
+  /* Note: this function is called by other C code on non-leaf
+     windows. */
+
+  /* Do the equivalent of decode_window() but don't error out on
+     deleted window; it's OK to delete an already-deleted window. */
+  if (NILP (window))
+    window = Fselected_window (Qnil);
+  else
+    CHECK_WINDOW (window);
+  w = XWINDOW (window);
+
+  /* It's okay to delete an already-deleted window.  */
+  if (! WINDOW_LIVE_P (w))
+    return Qnil;
+
+  frame = WINDOW_FRAME (w);
+  f = XFRAME (frame);
+  d = XDEVICE (FRAME_DEVICE (f));
+
+  if (TOP_LEVEL_WINDOW_P (w))
+    {
+      if (NILP (memq_no_quit (frame, DEVICE_FRAME_LIST (d))))
+	/* this frame isn't fully initialized yet; don't blow up. */
+	return Qnil;
+
+      if (MINI_WINDOW_P (XWINDOW (window)))
+	error ("Attempt to delete the minibuffer window");
+
+      /* It has been suggested that it's a good thing for C-x 0 to have this
+	 behavior, but not such a good idea for #'delete-window to have it.
+	 Maybe C-x 0 should be bound to something else, or maybe frame
+	 deletion should only happen when this is called interactively.
+       */
+      delete_frame_internal (f, !NILP (force), 0, 0);
+      return Qnil;
+    }
+
+  /* At this point, we know the window has a parent. */
+  parent = w->parent;
+  par = XWINDOW (parent);
+
+  MARK_FRAME_WINDOWS_STRUCTURE_CHANGED (f);
+
+  /* Are we trying to delete any frame's selected window?
+     Note that we could be dealing with a non-leaf window
+     where the selected window is one of our children.
+     So, we check by scanning all the ancestors of the
+     frame's selected window and comparing each one with
+     WINDOW.  */
+  {
+    Lisp_Object pwindow;
+
+    pwindow = FRAME_SELECTED_WINDOW (f);
+
+    while (!NILP (pwindow))
+      {
+	if (EQ (window, pwindow))
+	  break;
+	pwindow = XWINDOW (pwindow)->parent;
+      }
+
+    if (EQ (window, pwindow))
+      {
+	/* OK, we found it. */
+	Lisp_Object alternative;
+	alternative = Fnext_window (window, Qlambda, Qnil, Qnil);
+
+	/* If we're about to delete the selected window on the
+	   selected frame, then we should use Fselect_window to select
+	   the new window.  On the other hand, if we're about to
+	   delete the selected window on any other frame, we shouldn't do
+	   anything but set the frame's selected_window slot.  */
+	if (EQ (frame, Fselected_frame (Qnil)))
+	  Fselect_window (alternative, Qnil);
+	else
+	  set_frame_selected_window (f, alternative);
+      }
+  }
+
+  /* w->buffer is nil in a non-leaf window; in this case,
+     get rid of the markers we maintain that point into that buffer. */
+  if (!NILP (w->buffer))
+    {
+      unshow_buffer (w);
+      unchain_marker (w->pointm[CURRENT_DISP]);
+      unchain_marker (w->pointm[DESIRED_DISP]);
+      unchain_marker (w->pointm[CMOTION_DISP]);
+      unchain_marker (w->start[CURRENT_DISP]);
+      unchain_marker (w->start[DESIRED_DISP]);
+      unchain_marker (w->start[CMOTION_DISP]);
+      unchain_marker (w->sb_point);
+      /* This breaks set-window-configuration if windows in the saved
+	 configuration get deleted and multiple frames are in use. */
+      /* w->buffer = Qnil; */
+    }
+
+  /* close up the hole in the sibling list */
+  if (!NILP (w->next))
+    XWINDOW (w->next)->prev = w->prev;
+  if (!NILP (w->prev))
+    XWINDOW (w->prev)->next = w->next;
+  if (EQ (window, par->hchild))
+    par->hchild = w->next;
+  if (EQ (window, par->vchild))
+    par->vchild = w->next;
+
+  /* Find one of our siblings to give our space to.  */
+  {
+    Lisp_Object sib = w->prev;
+    if (NILP (sib))
+      {
+	/* If w gives its space to its next sibling, that sibling needs
+	   to have its top/left side pulled back to where w's is.
+	   set_window_{height,width} will re-position the sibling's
+	   children.  */
+	sib = w->next;
+	WINDOW_TOP (XWINDOW (sib)) = WINDOW_TOP (w);
+	WINDOW_LEFT (XWINDOW (sib)) = WINDOW_LEFT (w);
+      }
+
+    /* Stretch that sibling.  */
+    if (!NILP (par->vchild))
+      set_window_pixheight
+	(sib, (WINDOW_HEIGHT (XWINDOW (sib)) + WINDOW_HEIGHT (w)), 1);
+    if (!NILP (par->hchild))
+      set_window_pixwidth
+	(sib, (WINDOW_WIDTH (XWINDOW (sib)) + WINDOW_WIDTH (w)), 1);
+  }
+
+  /* If parent now has only one child,
+     put the child into the parent's place.  */
+  {
+    Lisp_Object parchild = par->hchild;
+    if (NILP (parchild))
+      parchild = par->vchild;
+    if (NILP (XWINDOW (parchild)->next))
+      {
+	replace_window (parent, parchild);
+	mark_window_as_deleted (XWINDOW (parent));
+      }
+  }
+
+  /* Since we may be deleting combination windows, we must make sure that
+     not only W but all its children have been marked as deleted.  */
+  if (!NILP (w->hchild))
+    delete_all_subwindows (XWINDOW (w->hchild));
+  else if (!NILP (w->vchild))
+    delete_all_subwindows (XWINDOW (w->vchild));
+
+  mark_window_as_deleted (w);
+
+  f->mirror_dirty = 1;
+  return Qnil;
+}
+
+
+DEFUN ("next-window", Fnext_window, 0, 4, 0, /*
+Return next window after WINDOW in canonical ordering of windows.
+If omitted, WINDOW defaults to the selected window.
+
+Optional second arg MINIBUF t means count the minibuffer window even
+if not active.  MINIBUF nil or omitted means count the minibuffer iff
+it is active.  MINIBUF neither t nor nil means not to count the
+minibuffer even if it is active.
+
+Several frames may share a single minibuffer; if the minibuffer
+counts, all windows on all frames that share that minibuffer count
+too.  Therefore, `next-window' can be used to iterate through the
+set of windows even when the minibuffer is on another frame.  If the
+minibuffer does not count, only windows from WINDOW's frame count.
+
+Optional third arg ALL-FRAMES t means include windows on all frames.
+ALL-FRAMES nil or omitted means cycle within the frames as specified
+above.  ALL-FRAMES = `visible' means include windows on all visible frames.
+ALL-FRAMES = 0 means include windows on all visible and iconified frames.
+If ALL-FRAMES is a frame, restrict search to windows on that frame.
+Anything else means restrict to WINDOW's frame.
+
+Optional fourth argument CONSOLE controls which consoles or devices the
+returned window may be on.  If CONSOLE is a console, return windows only
+on that console.  If CONSOLE is a device, return windows only on that
+device.  If CONSOLE is a console type, return windows only on consoles
+of that type.  If CONSOLE is 'window-system, return any windows on any
+window-system consoles.  If CONSOLE is nil or omitted, return windows only
+on WINDOW's console.  Otherwise, all windows are considered.
+
+If you use consistent values for MINIBUF, ALL-FRAMES, and CONSOLE, you
+can use `next-window' to iterate through the entire cycle of acceptable
+windows, eventually ending up back at the window you started with.
+`previous-window' traverses the same cycle, in the reverse order.
+*/
+     (window, minibuf, all_frames, console))
+{
+  Lisp_Object tem;
+  Lisp_Object start_window;
+
+  if (NILP (window))
+    window = Fselected_window (Qnil);
+  else
+    CHECK_LIVE_WINDOW (window);
+
+  start_window = window;
+
+  /* minibuf == nil may or may not include minibuffers.
+     Decide if it does.  */
+  if (NILP (minibuf))
+    minibuf = (minibuf_level ? minibuf_window : Qlambda);
+  else if (! EQ (minibuf, Qt))
+    minibuf = Qlambda;
+  /* Now minibuf can be t => count all minibuffer windows,
+     lambda => count none of them,
+     or a specific minibuffer window (the active one) to count.  */
+
+  /* all_frames == nil doesn't specify which frames to include.  */
+  if (NILP (all_frames))
+    all_frames = (! EQ (minibuf, Qlambda)
+		  ? (FRAME_MINIBUF_WINDOW
+		     (XFRAME
+		      (WINDOW_FRAME
+		       (XWINDOW (window)))))
+		  : Qnil);
+  else if (EQ (all_frames, Qvisible))
+    ;
+  else if (ZEROP (all_frames))
+    ;
+  else if (FRAMEP (all_frames) && ! EQ (all_frames, Fwindow_frame (window)))
+    /* If all_frames is a frame and window arg isn't on that frame, just
+       return the first window on the frame.  */
+    return frame_first_window (XFRAME (all_frames));
+  else if (! EQ (all_frames, Qt))
+    all_frames = Qnil;
+  /* Now all_frames is t meaning search all frames,
+     nil meaning search just current frame,
+     visible meaning search just visible frames,
+     0 meaning search visible and iconified frames,
+     or a window, meaning search the frame that window belongs to.  */
+
+  /* Do this loop at least once, to get the next window, and perhaps
+     again, if we hit the minibuffer and that is not acceptable.  */
+  do
+    {
+      /* Find a window that actually has a next one.  This loop
+	 climbs up the tree.  */
+      while (tem = XWINDOW (window)->next, NILP (tem))
+	if (tem = XWINDOW (window)->parent, !NILP (tem))
+	  window = tem;
+        else  /* window must be minibuffer window now */
+	  {
+	    /* We've reached the end of this frame.
+	       Which other frames are acceptable?  */
+	    tem = WINDOW_FRAME (XWINDOW (window));
+
+	    if (! NILP (all_frames))
+	      {
+		Lisp_Object tem1;
+
+		tem1 = tem;
+		tem = next_frame (tem, all_frames, console);
+		/* In the case where the minibuffer is active,
+		   and we include its frame as well as the selected one,
+		   next_frame may get stuck in that frame.
+		   If that happens, go back to the selected frame
+		   so we can complete the cycle.  */
+		if (EQ (tem, tem1))
+		  XSETFRAME (tem, selected_frame ());
+	      }
+
+	    tem = FRAME_ROOT_WINDOW (XFRAME (tem));
+	    break;
+	  }
+
+      window = tem;
+
+      /* If we're in a combination window, find its first child and
+	 recurse on that.  Otherwise, we've found the window we want.  */
+      while (1)
+	{
+	  if (!NILP (XWINDOW (window)->hchild))
+	    window = XWINDOW (window)->hchild;
+	  else if (!NILP (XWINDOW (window)->vchild))
+	    window = XWINDOW (window)->vchild;
+	  else break;
+	}
+    }
+  /* "acceptable" is the correct spelling. */
+  /* Which windows are acceptable?
+     Exit the loop and accept this window if
+     this isn't a minibuffer window,
+     or we're accepting all minibuffer windows,
+     or this is the active minibuffer and we are accepting that one, or
+     we've come all the way around and we're back at the original window.  */
+  while (MINI_WINDOW_P (XWINDOW (window))
+	 && ! EQ (minibuf, Qt)
+	 && ! EQ (minibuf, window)
+	 && ! EQ (window, start_window));
+
+  return window;
+}
+
+DEFUN ("previous-window", Fprevious_window, 0, 4, 0, /*
+Return the window preceding WINDOW in canonical ordering of windows.
+If omitted, WINDOW defaults to the selected window.
+
+Optional second arg MINIBUF t means count the minibuffer window even
+if not active.  MINIBUF nil or omitted means count the minibuffer iff
+it is active.  MINIBUF neither t nor nil means not to count the
+minibuffer even if it is active.
+
+Several frames may share a single minibuffer; if the minibuffer
+counts, all windows on all frames that share that minibuffer count
+too.  Therefore, `previous-window' can be used to iterate through
+the set of windows even when the minibuffer is on another frame.  If
+the minibuffer does not count, only windows from WINDOW's frame count
+
+If optional third arg ALL-FRAMES t means include windows on all frames.
+ALL-FRAMES nil or omitted means cycle within the frames as specified
+above.  ALL-FRAMES = `visible' means include windows on all visible frames.
+ALL-FRAMES = 0 means include windows on all visible and iconified frames.
+If ALL-FRAMES is a frame, restrict search to windows on that frame.
+Anything else means restrict to WINDOW's frame.
+
+Optional fourth argument CONSOLE controls which consoles or devices the
+returned window may be on.  If CONSOLE is a console, return windows only
+on that console.  If CONSOLE is a device, return windows only on that
+device.  If CONSOLE is a console type, return windows only on consoles
+of that type.  If CONSOLE is 'window-system, return any windows on any
+window-system consoles.  If CONSOLE is nil or omitted, return windows only
+on WINDOW's console.  Otherwise, all windows are considered.
+
+If you use consistent values for MINIBUF, ALL-FRAMES, and CONSOLE, you
+can use `previous-window' to iterate through the entire cycle of acceptable
+windows, eventually ending up back at the window you started with.
+`next-window' traverses the same cycle, in the reverse order.
+*/
+     (window, minibuf, all_frames, console))
+{
+  Lisp_Object tem;
+  Lisp_Object start_window;
+
+  if (NILP (window))
+    window = Fselected_window (Qnil);
+  else
+    CHECK_LIVE_WINDOW (window);
+
+  start_window = window;
+
+  /* minibuf == nil may or may not include minibuffers.
+     Decide if it does.  */
+  if (NILP (minibuf))
+    minibuf = (minibuf_level ? minibuf_window : Qlambda);
+  else if (! EQ (minibuf, Qt))
+    minibuf = Qlambda;
+  /* Now minibuf can be t => count all minibuffer windows,
+     lambda => count none of them,
+     or a specific minibuffer window (the active one) to count.  */
+
+  /* all_frames == nil doesn't specify which frames to include.
+     Decide which frames it includes.  */
+  if (NILP (all_frames))
+    all_frames = (! EQ (minibuf, Qlambda)
+		  ? (FRAME_MINIBUF_WINDOW
+		     (XFRAME
+		      (WINDOW_FRAME
+		       (XWINDOW (window)))))
+		  : Qnil);
+  else if (EQ (all_frames, Qvisible))
+    ;
+  else if (ZEROP (all_frames))
+    ;
+  else if (FRAMEP (all_frames) && ! EQ (all_frames, Fwindow_frame (window)))
+    /* If all_frames is a frame and window arg isn't on that frame, just
+       return the first window on the frame.  */
+    return frame_first_window (XFRAME (all_frames));
+  else if (! EQ (all_frames, Qt))
+    all_frames = Qnil;
+  /* Now all_frames is t meaning search all frames,
+     nil meaning search just current frame,
+     visible meaning search just visible frames,
+     0 meaning search visible and iconified frames,
+     or a window, meaning search the frame that window belongs to.  */
+
+  /* Do this loop at least once, to get the next window, and perhaps
+     again, if we hit the minibuffer and that is not acceptable.  */
+  do
+    {
+      /* Find a window that actually has a next one.  This loop
+	 climbs up the tree.  */
+      while (tem = XWINDOW (window)->prev, NILP (tem))
+	if (tem = XWINDOW (window)->parent, !NILP (tem))
+	  window = tem;
+        else  /* window must be minibuffer window now */
+	  {
+	    /* We have found the top window on the frame.
+	       Which frames are acceptable?  */
+	    tem = WINDOW_FRAME (XWINDOW (window));
+
+	    if (! NILP (all_frames))
+	      /* It's actually important that we use prev_frame here,
+		 rather than next_frame.  All the windows acceptable
+		 according to the given parameters should form a ring;
+		 Fnext_window and Fprevious_window should go back and
+		 forth around the ring.  If we use next_frame here,
+		 then Fnext_window and Fprevious_window take different
+		 paths through the set of acceptable windows.
+		 window_loop assumes that these `ring' requirement are
+		 met.  */
+	      {
+		Lisp_Object tem1;
+
+		tem1 = tem;
+		tem = prev_frame (tem, all_frames, console);
+		/* In the case where the minibuffer is active,
+		   and we include its frame as well as the selected one,
+		   next_frame may get stuck in that frame.
+		   If that happens, go back to the selected frame
+		   so we can complete the cycle.  */
+		if (EQ (tem, tem1))
+		  XSETFRAME (tem, selected_frame ());
+	      }
+
+	    /* If this frame has a minibuffer, find that window first,
+	       because it is conceptually the last window in that frame.  */
+	    if (FRAME_HAS_MINIBUF_P (XFRAME (tem)))
+	      tem = FRAME_MINIBUF_WINDOW (XFRAME (tem));
+	    else
+	      tem = FRAME_ROOT_WINDOW (XFRAME (tem));
+
+	    break;
+	  }
+
+      window = tem;
+
+      /* If we're in a combination window, find its first child and
+	 recurse on that.  Otherwise, we've found the window we want.  */
+      while (1)
+	{
+	  if (!NILP (XWINDOW (window)->hchild))
+	    window = XWINDOW (window)->hchild;
+	  else if (!NILP (XWINDOW (window)->vchild))
+	    window = XWINDOW (window)->vchild;
+	  else break;
+	  while (tem = XWINDOW (window)->next, !NILP (tem))
+	    window = tem;
+	}
+    }
+  /* Which windows are acceptable?
+     Exit the loop and accept this window if
+     this isn't a minibuffer window,
+     or we're accepting all minibuffer windows,
+     or this is the active minibuffer and we are accepting that one, or
+     we've come all the way around and we're back at the original window.  */
+  while (MINI_WINDOW_P (XWINDOW (window))
+	 && ! EQ (minibuf, Qt)
+	 && ! EQ (minibuf, window)
+	 && ! EQ (window, start_window));
+
+  return window;
+}
+
+DEFUN ("next-vertical-window", Fnext_vertical_window, 0, 1, 0, /*
+Return the next window which is vertically after WINDOW.
+*/
+       (window))
+{
+  Lisp_Object root;
+  struct window *w = decode_window (window);
+  XSETWINDOW (window, w);
+
+  if (MINI_WINDOW_P (XWINDOW (window)))
+    return Qnil;
+
+  root = FRAME_ROOT_WINDOW (XFRAME (WINDOW_FRAME (XWINDOW (window))));
+
+  if (EQ (window, root))
+    {
+      while (1)
+	if (!NILP (XWINDOW (window)->hchild))
+	  window = XWINDOW (window)->hchild;
+	else if (!NILP (XWINDOW (window)->vchild))
+	  window = XWINDOW (window)->vchild;
+	else
+	  return window;
+    }
+
+  do
+    {
+      if (!NILP (XWINDOW (window)->parent) &&
+	  !NILP (XWINDOW (XWINDOW (window)->parent)->vchild))
+	{
+	  if (!NILP (XWINDOW (window)->next))
+	    return XWINDOW (window)->next;
+	  else
+	    window = XWINDOW (window)->parent;
+	}
+      else
+	window = XWINDOW (window)->parent;
+    }
+  while (!EQ (window, root));
+
+  while (1)
+    if (!NILP (XWINDOW (window)->hchild))
+      window = XWINDOW (window)->hchild;
+    else if (!NILP (XWINDOW (window)->vchild))
+      window = XWINDOW (window)->vchild;
+    else
+      return window;
+}
+
+DEFUN ("other-window", Fother_window, 1, 3, "p", /*
+Select the N'th different window on this frame.
+All windows on current frame are arranged in a cyclic order.
+This command selects the window N steps away in that order.
+A negative N moves in the opposite order.
+
+If optional argument FRAME is `visible', search all visible frames.
+If FRAME is 0, search all visible and iconified frames.
+If FRAME is t, search all frames.
+If FRAME is nil, search only the selected frame.
+If FRAME is a frame, search only that frame.
+
+Optional third argument CONSOLE controls which consoles or devices the
+returned window may be on.  If CONSOLE is a console, return windows only
+on that console.  If CONSOLE is a device, return windows only on that
+device.  If CONSOLE is a console type, return windows only on consoles
+of that type.  If CONSOLE is 'window-system, return any windows on any
+window-system consoles.  If CONSOLE is nil or omitted, return windows only
+on FRAME'S console, or on the selected console if FRAME is not a frame.
+Otherwise, all windows are considered.
+*/
+       (n, frame, console))
+{
+  int i;
+  Lisp_Object w;
+
+  CHECK_INT (n);
+  w = Fselected_window (Qnil);
+  i = XINT (n);
+
+  while (i > 0)
+    {
+      w = Fnext_window (w, Qnil, frame, console);
+      i--;
+    }
+  while (i < 0)
+    {
+      w = Fprevious_window (w, Qnil, frame, console);
+      i++;
+    }
+  Fselect_window (w, Qnil);
+  return Qnil;
+}
+
+
+/* Look at all windows, performing an operation specified by TYPE
+   with argument OBJ.
+
+   If FRAMES is Qt, look at all frames, if Qnil, look at just the selected
+   frame.  If FRAMES is a frame, just look at windows on that frame.
+   If MINI is non-zero, perform the operation on minibuffer windows too.
+*/
+
+enum window_loop
+{
+  WINDOW_LOOP_UNUSED,
+  GET_BUFFER_WINDOW,		/* Arg is buffer */
+  GET_LRU_WINDOW,		/* Arg is t for full-width windows only */
+  DELETE_OTHER_WINDOWS,		/* Arg is window not to delete */
+  DELETE_BUFFER_WINDOWS,	/* Arg is buffer */
+  GET_LARGEST_WINDOW,
+  UNSHOW_BUFFER,		/* Arg is buffer */
+  GET_BUFFER_WINDOW_COUNT,	/* Arg is buffer */
+  GET_BUFFER_MRU_WINDOW		/* Arg is buffer */
+};
+
+static Lisp_Object
+window_loop (enum window_loop type,
+             Lisp_Object obj,
+             int mini,
+             Lisp_Object frames,
+	     int dedicated_too,
+	     Lisp_Object console)
+{
+  /* This function can GC if type == DELETE_BUFFER_WINDOWS or UNSHOW_BUFFER */
+  Lisp_Object w;
+  Lisp_Object best_window = Qnil;
+  Lisp_Object next_window;
+  Lisp_Object last_window;
+  struct frame *frame;
+  Lisp_Object frame_arg = Qt;
+  int count = 0;		/* for GET_BUFFER_WINDOW_COUNT */
+  /* #### I think the change of "precomputing" last_window and next_window
+   * ####  catch the lossage this is meant(?) to punt on...
+   */
+  int lose_lose = 0;
+  Lisp_Object devcons, concons;
+
+  /* FRAME_ARG is Qlambda to stick to one frame,
+     Qvisible to consider all visible frames,
+     or Qt otherwise.  */
+
+  /* If we're only looping through windows on a particular frame,
+     FRAME points to that frame.  If we're looping through windows
+     on all frames, FRAME is 0.  */
+
+  if (FRAMEP (frames))
+    frame = XFRAME (frames);
+  else if (NILP (frames))
+    frame = selected_frame ();
+  else
+    frame = 0;
+  if (frame)
+    frame_arg = Qlambda;
+  else if (ZEROP (frames))
+    frame_arg = frames;
+  else if (EQ (frames, Qvisible))
+    frame_arg = frames;
+
+  DEVICE_LOOP_NO_BREAK (devcons, concons)
+    {
+      Lisp_Object device = XCAR (devcons);
+      Lisp_Object the_frame;
+
+      if (frame)
+	XSETFRAME (the_frame, frame);
+      else
+	the_frame = DEVICE_SELECTED_FRAME (XDEVICE (device));
+
+      if (NILP (the_frame))
+	continue;
+
+      if (!device_matches_console_spec (the_frame, device, console))
+	continue;
+
+      /* Pick a window to start with.  */
+      if (WINDOWP (obj))
+	w = obj;
+      else
+	w = FRAME_SELECTED_WINDOW (XFRAME (the_frame));
+
+      /* Figure out the last window we're going to mess with.  Since
+	 Fnext_window, given the same options, is guaranteed to go in a
+	 ring, we can just use Fprevious_window to find the last one.
+
+	 We can't just wait until we hit the first window again,
+	 because it might be deleted.  */
+
+      last_window = Fprevious_window (w, mini ? Qt : Qnil, frame_arg, Qt);
+
+      best_window = Qnil;
+      for (;;)
+	{
+	  struct window *p = XWINDOW (w);
+	  struct frame *w_frame = XFRAME (WINDOW_FRAME (p));
+
+	  /* Pick the next window now, since some operations will delete
+	     the current window.  */
+	  next_window = Fnext_window (w, mini ? Qt : Qnil, frame_arg, Qt);
+
+	  /* #### Still needed ?? */
+	  /* Given the outstanding quality of the rest of this code,
+	     I feel no shame about putting this piece of shit in. */
+	  if (++lose_lose >= 500)
+	    return Qnil;
+
+	  /* Note that we do not pay attention here to whether
+	     the frame is visible, since Fnext_window skips non-visible frames
+	     if that is desired, under the control of frame_arg.  */
+	  if (! MINI_WINDOW_P (p)
+	      || (mini && minibuf_level > 0))
+	    switch (type)
+	      {
+	      case GET_BUFFER_WINDOW:
+		{
+		  if (XBUFFER (p->buffer) == XBUFFER (obj))
+		    return w;
+		  break;
+		}
+
+	      case GET_BUFFER_WINDOW_COUNT:
+		{
+		  if (XBUFFER (p->buffer) == XBUFFER (obj))
+		    count++;
+		  break;
+		}
+
+	      case GET_LRU_WINDOW:
+		{
+		  /* t as arg means consider only full-width windows */
+		  if (!NILP (obj)
+		      && !window_full_width_p (p))
+		    break;
+		  /* Ignore dedicated windows and minibuffers.  */
+		  if (MINI_WINDOW_P (p)
+		      || (dedicated_too ? 0 : !NILP (p->dedicated)))
+		    break;
+		  if (NILP (best_window)
+		      || (XINT (XWINDOW (best_window)->use_time)
+			  > XINT (p->use_time)))
+		    best_window = w;
+		  break;
+		}
+
+	      case GET_BUFFER_MRU_WINDOW:
+		{
+		  /* #### what about the first check in GET_LRU_WINDOW? */
+		  /* Ignore dedicated windows and minibuffers. */
+		  if (MINI_WINDOW_P (p)
+		      || (dedicated_too ? 0 : !NILP (p->dedicated)))
+		    break;
+
+		  if (XBUFFER (p->buffer) == XBUFFER (obj))
+		    {
+		      if (NILP (best_window)
+			  || (XINT (XWINDOW (best_window)->use_time)
+			      < XINT (p->use_time)))
+			best_window = w;
+		    }
+		  break;
+		}
+
+	      case DELETE_OTHER_WINDOWS:
+		{
+		  /* Don't delete the last window on a frame; this can
+		     happen when the minibuffer is selected, and would
+		     cause the frame to be deleted. */
+		  if (p != XWINDOW (obj) && !TOP_LEVEL_WINDOW_P (XWINDOW (w)))
+		    Fdelete_window (w, Qnil);
+		  break;
+		}
+
+	      case DELETE_BUFFER_WINDOWS:
+		{
+		  if (EQ (p->buffer, obj))
+		    {
+		      struct frame *f = XFRAME (WINDOW_FRAME (p));
+
+		      /* If this window is dedicated, and in a frame
+			 of its own, kill the frame.  */
+		      if (EQ (w, FRAME_ROOT_WINDOW (f))
+			  && !NILP (p->dedicated)
+			  && other_visible_frames (f))
+			{
+			  /* Skip the other windows on this frame.
+			     There might be one, the minibuffer!  */
+			  if (! EQ (w, last_window))
+			    while (f == XFRAME (WINDOW_FRAME
+						(XWINDOW (next_window))))
+			      {
+				/* As we go, check for the end of the
+				   loop.  We mustn't start going
+				   around a second time.  */
+				if (EQ (next_window, last_window))
+				  {
+				    last_window = w;
+				    break;
+				  }
+				next_window = Fnext_window (next_window,
+							    mini ? Qt : Qnil,
+							    frame_arg, Qt);
+			      }
+			  /* Now we can safely delete the frame.  */
+			  Fdelete_frame (WINDOW_FRAME (p), Qnil);
+			}
+		      else
+			/* If we're deleting the buffer displayed in
+			   the only window on the frame, find a new
+			   buffer to display there.  */
+			if (NILP (p->parent))
+			  {
+			    Lisp_Object new_buffer;
+			    new_buffer = Fother_buffer (obj, Qnil, Qnil);
+			    if (NILP (new_buffer))
+			      new_buffer = Fget_buffer_create (QSscratch);
+			    Fset_window_buffer (w, new_buffer);
+			    if (EQ (w, Fselected_window (Qnil)))
+			      Fset_buffer (p->buffer);
+			  }
+			else
+			  Fdelete_window (w, Qnil);
+		    }
+		  break;
+		}
+
+	      case GET_LARGEST_WINDOW:
+		{
+		  /* Ignore dedicated windows and minibuffers.  */
+		  if (MINI_WINDOW_P (p)
+		      || (dedicated_too ? 0 : !NILP (p->dedicated)))
+		    break;
+		  {
+		    /* write the check as follows to avoid tripping
+		       error_check_window() --ben */
+		    struct window *b = NILP (best_window) ? 0 :
+		      XWINDOW (best_window);
+		    if (NILP (best_window)
+			|| ((WINDOW_HEIGHT (p) * WINDOW_WIDTH (p))
+			    > (WINDOW_HEIGHT (b) * WINDOW_WIDTH (b))))
+		      best_window = w;
+		  }
+		  break;
+		}
+
+	      case UNSHOW_BUFFER:
+		{
+		  if (EQ (p->buffer, obj))
+		    {
+		      /* Find another buffer to show in this window.  */
+		      Lisp_Object another_buffer =
+			Fother_buffer (obj, Qnil, Qnil);
+		      if (NILP (another_buffer))
+			another_buffer
+			  = Fget_buffer_create (QSscratch);
+		      /* If this window is dedicated, and in a frame
+			 of its own, kill the frame.  */
+		      if (EQ (w, FRAME_ROOT_WINDOW (w_frame))
+			  && !NILP (p->dedicated)
+			  && other_visible_frames (w_frame))
+			{
+			  /* Skip the other windows on this frame.
+			     There might be one, the minibuffer!  */
+			  if (! EQ (w, last_window))
+			    while (w_frame == XFRAME (WINDOW_FRAME
+						      (XWINDOW (next_window))))
+			      {
+				/* As we go, check for the end of the
+				   loop.  We mustn't start going
+				   around a second time.  */
+				if (EQ (next_window, last_window))
+				  {
+				    last_window = w;
+				    break;
+				  }
+				next_window = Fnext_window (next_window,
+							    mini ? Qt : Qnil,
+							    frame_arg, Qt);
+			      }
+			  /* Now we can safely delete the frame.  */
+			  delete_frame_internal (XFRAME (WINDOW_FRAME (p)),
+						 0, 0, 0);
+			}
+		      else
+			{
+			  /* Otherwise show a different buffer in the
+                             window.  */
+			  p->dedicated = Qnil;
+			  Fset_window_buffer (w, another_buffer);
+			  if (EQ (w, Fselected_window (Qnil)))
+			    Fset_buffer (p->buffer);
+			}
+		    }
+		  break;
+		}
+
+	      default:
+		abort ();
+	      }
+
+	  if (EQ (w, last_window))
+	    break;
+
+	  w = next_window;
+	}
+    }
+
+  return type == GET_BUFFER_WINDOW_COUNT ? make_int (count) : best_window;
+}
+
+#if 0 /* not currently used */
+
+int
+buffer_window_count (struct buffer *b, struct frame *f)
+{
+  Lisp_Object buffer, frame;
+
+  XSETFRAME (frame, f);
+  XSETBUFFER (buffer, b);
+
+  return XINT (window_loop (GET_BUFFER_WINDOW_COUNT, buffer, 0, frame, 1,
+			    Qnil));
+}
+
+int
+buffer_window_mru (struct window *w)
+{
+  Lisp_Object window =
+    window_loop (GET_BUFFER_MRU_WINDOW, w->buffer, 0, w->frame, 1, Qnil);
+
+  if (NILP (window))
+    return 0;
+  else if (XWINDOW (window) == w)
+    return 1;
+  else
+    return 0;
+}
+
+#endif
+
+
+DEFUN ("get-lru-window", Fget_lru_window, 0, 2, 0, /*
+Return the window least recently selected or used for display.
+If optional argument FRAME is `visible', search all visible frames.
+If FRAME is 0, search all visible and iconified frames.
+If FRAME is t, search all frames.
+If FRAME is nil, search only the selected frame.
+If FRAME is a frame, search only that frame.
+
+Optional second argument CONSOLE controls which consoles or devices the
+returned window may be on.  If CONSOLE is a console, return windows only
+on that console.  If CONSOLE is a device, return windows only on that
+device.  If CONSOLE is a console type, return windows only on consoles
+of that type.  If CONSOLE is 'window-system, return any windows on any
+window-system consoles.  If CONSOLE is nil or omitted, return windows only
+on FRAME'S console, or on the selected console if FRAME is not a frame.
+Otherwise, all windows are considered.
+*/
+       (frame, console))
+{
+  Lisp_Object w;
+  /* First try for a non-dedicated window that is full-width */
+  w = window_loop (GET_LRU_WINDOW, Qt, 0, frame, 0, console);
+  if (!NILP (w) && !EQ (w, Fselected_window (Qnil)))
+    return w;
+
+  /* Then try for any non-dedicated window */
+  w = window_loop (GET_LRU_WINDOW, Qnil, 0, frame, 0, console);
+  if (!NILP (w) && !EQ (w, Fselected_window (Qnil)))
+    return w;
+
+#if 0
+  /* FSFmacs never returns a dedicated window here.  If we do,
+     it makes `display-buffer' not work right.  #### All of this
+     shit is so disgusting and awful that it needs to be rethought
+     from scratch. */
+  /* then try for a dedicated window that is full-width */
+  w = window_loop (GET_LRU_WINDOW, Qt, 0, frame, 1, console);
+  if (!NILP (w) && !EQ (w, Fselected_window (Qnil)))
+    return w;
+
+  /* If none of them, then all windows, dedicated or not. */
+  w = window_loop (GET_LRU_WINDOW, Qnil, 0, frame, 1, console);
+
+  /* At this point we damn well better have found something. */
+  if (NILP (w)) abort ();
+#endif
+
+  return w;
+}
+
+DEFUN ("get-largest-window", Fget_largest_window, 0, 2, 0, /*
+Return the window largest in area.
+If optional argument FRAME is `visible', search all visible frames.
+If FRAME is 0, search all visible and iconified frames.
+If FRAME is t, search all frames.
+If FRAME is nil, search only the selected frame.
+If FRAME is a frame, search only that frame.
+
+Optional second argument CONSOLE controls which consoles or devices the
+returned window may be on.  If CONSOLE is a console, return windows only
+on that console.  If CONSOLE is a device, return windows only on that
+device.  If CONSOLE is a console type, return windows only on consoles
+of that type.  If CONSOLE is 'window-system, return any windows on any
+window-system consoles.  If CONSOLE is nil or omitted, return windows only
+on FRAME'S console, or on the selected console if FRAME is not a frame.
+Otherwise, all windows are considered.
+*/
+       (frame, console))
+{
+  /* Don't search dedicated windows because FSFmacs doesn't.
+     This stuff is all black magic so don't try to apply common
+     sense to it. */
+  return window_loop (GET_LARGEST_WINDOW, Qnil, 0, frame, 0, console);
+}
+
+DEFUN ("get-buffer-window", Fget_buffer_window, 1, 3, 0, /*
+Return a window currently displaying BUFFER, or nil if none.
+If optional argument FRAME is `visible', search all visible frames.
+If optional argument FRAME is 0, search all visible and iconified frames.
+If FRAME is t, search all frames.
+If FRAME is nil, search only the selected frame.
+If FRAME is a frame, search only that frame.
+
+Optional third argument CONSOLE controls which consoles or devices the
+returned window may be on.  If CONSOLE is a console, return windows only
+on that console.  If CONSOLE is a device, return windows only on that
+device.  If CONSOLE is a console type, return windows only on consoles
+of that type.  If CONSOLE is 'window-system, return any windows on any
+window-system consoles.  If CONSOLE is nil or omitted, return windows only
+on FRAME'S console, or on the selected console if FRAME is not a frame.
+Otherwise, all windows are considered.
+*/
+       (buffer, frame, console))
+{
+  buffer = Fget_buffer (buffer);
+  if (BUFFERP (buffer))
+    /* Search dedicated windows too. (Doesn't matter here anyway.) */
+    return window_loop (GET_BUFFER_WINDOW, buffer, 1, frame, 1, console);
+  else
+    return Qnil;
+}
+
+/* These functions used to be `buffer-left-margin-pixel-width', etc.
+   but there is no sensible way to implement those functions, since
+   you can't in general derive a window from a buffer. */
+
+DEFUN ("window-left-margin-pixel-width", Fwindow_left_margin_pixel_width,
+       0, 1, 0, /*
+Return the width in pixels of the left outside margin of window WINDOW.
+If WINDOW is nil, the selected window is assumed.
+*/
+       (window))
+{
+  return make_int (window_left_margin_width (decode_window (window)));
+}
+
+DEFUN ("window-right-margin-pixel-width", Fwindow_right_margin_pixel_width,
+       0, 1, 0, /*
+Return the width in pixels of the right outside margin of window WINDOW.
+If WINDOW is nil, the selected window is assumed.
+*/
+       (window))
+{
+  return make_int (window_right_margin_width (decode_window (window)));
+}
+
+DEFUN ("delete-other-windows", Fdelete_other_windows, 0, 1, "", /*
+Make WINDOW (or the selected window) fill its frame.
+Only the frame WINDOW is on is affected.
+This function tries to reduce display jumps
+by keeping the text previously visible in WINDOW
+in the same place on the frame.  Doing this depends on
+the value of (window-start WINDOW), so if calling this function
+in a program gives strange scrolling, make sure the window-start
+value is reasonable when this function is called.
+*/
+       (window))
+{
+  struct window *w = decode_window (window);
+  struct buffer *b = XBUFFER (w->buffer);
+  Bufpos start_pos;
+  int old_top = WINDOW_TOP (w);
+
+  XSETWINDOW (window, w);
+
+  if (MINI_WINDOW_P (w) && old_top > 0)
+    error ("Can't expand minibuffer to full frame");
+
+  /* Ignore dedicated windows. */
+  window_loop (DELETE_OTHER_WINDOWS, window, 0, w->frame, 0, Qnil);
+
+  start_pos = marker_position (w->start[CURRENT_DISP]);
+
+  /* Try to minimize scrolling, by setting the window start to the
+     point which will cause the text at the old window start to be at
+     the same place on the frame.  But don't try to do this if the
+     window start is outside the visible portion (as might happen when
+     the display is not current, due to typeahead). */
+  if (start_pos >= BUF_BEGV (b) && start_pos <= BUF_ZV (b)
+      && !MINI_WINDOW_P (w))
+    {
+      Bufpos new_start = start_with_line_at_pixpos (w, start_pos, old_top);
+
+      if (new_start >= BUF_BEGV (b) && new_start <= BUF_ZV (b))
+	{
+	  Fset_marker (w->start[CURRENT_DISP], make_int (new_start),
+		       w->buffer);
+	  w->start_at_line_beg = beginning_of_line_p (b, new_start);
+	}
+      /* We need to do this, so that the window-scroll-functions
+	 get called.  */
+      w->force_start = 1;
+    }
+
+  return Qnil;
+}
+
+DEFUN ("delete-windows-on", Fdelete_windows_on, 1, 3,
+       "bDelete windows on (buffer): ", /*
+Delete all windows showing BUFFER.
+Optional second argument FRAME controls which frames are affected.
+If nil or omitted, delete all windows showing BUFFER in any frame.
+If t, delete only windows showing BUFFER in the selected frame.
+If `visible', delete all windows showing BUFFER in any visible frame.
+If a frame, delete only windows showing BUFFER in that frame.
+
+Optional third argument CONSOLE controls which consoles or devices the
+returned window may be on.  If CONSOLE is a console, return windows only
+on that console.  If CONSOLE is a device, return windows only on that
+device.  If CONSOLE is a console type, return windows only on consoles
+of that type.  If CONSOLE is 'window-system, return any windows on any
+window-system consoles.  If CONSOLE is nil or omitted, return windows only
+on FRAME'S console, or on the selected console if FRAME is not a frame.
+Otherwise, all windows are considered.
+*/
+       (buffer, frame, console))
+{
+  /* This function can GC */
+  /* FRAME uses t and nil to mean the opposite of what window_loop
+     expects. */
+  if (!FRAMEP (frame))
+    frame = NILP (frame) ? Qt : Qnil;
+
+  if (!NILP (buffer))
+    {
+      buffer = Fget_buffer (buffer);
+      CHECK_BUFFER (buffer);
+      /* Ignore dedicated windows. */
+      window_loop (DELETE_BUFFER_WINDOWS, buffer, 0, frame, 0, console);
+    }
+  return Qnil;
+}
+
+DEFUN ("replace-buffer-in-windows", Freplace_buffer_in_windows, 1, 1,
+       "bReplace buffer in windows: ", /*
+Replace BUFFER with some other buffer in all windows showing it.
+*/
+       (buffer))
+{
+  /* This function can GC */
+  if (!NILP (buffer))
+    {
+      buffer = Fget_buffer (buffer);
+      CHECK_BUFFER (buffer);
+      /* Ignore dedicated windows. */
+      window_loop (UNSHOW_BUFFER, buffer, 0, Qt, 0, Qnil);
+    }
+  return Qnil;
+}
+
+/* The smallest acceptable dimensions for a window.  Anything smaller
+   might crash Emacs.  */
+#define MIN_SAFE_WINDOW_WIDTH  (2)
+#define MIN_SAFE_WINDOW_HEIGHT (2)
+
+/* Make sure that window_min_height and window_min_width are
+   not too small; if they are, set them to safe minima.  */
+
+static void
+check_min_window_sizes (void)
+{
+  /* Smaller values might permit a crash.  */
+  if (window_min_width < MIN_SAFE_WINDOW_WIDTH)
+    window_min_width = MIN_SAFE_WINDOW_WIDTH;
+  if (window_min_height < MIN_SAFE_WINDOW_HEIGHT)
+    window_min_height = MIN_SAFE_WINDOW_HEIGHT;
+}
+
+/* If *ROWS or *COLS are too small a size for FRAME, set them to the
+   minimum allowable size.  */
+void
+check_frame_size (struct frame *frame, int *rows, int *cols)
+{
+  /* For height, we have to see whether the frame has a minibuffer, and
+     whether it wants a modeline.  */
+  int min_height =
+    (FRAME_MINIBUF_ONLY_P (frame) ? MIN_SAFE_WINDOW_HEIGHT - 1
+     : (! FRAME_HAS_MINIBUF_P (frame)) ? MIN_SAFE_WINDOW_HEIGHT
+     : 2 * MIN_SAFE_WINDOW_HEIGHT - 1);
+
+  if (*rows < min_height)
+    *rows = min_height;
+  if (*cols  < MIN_SAFE_WINDOW_WIDTH)
+    *cols = MIN_SAFE_WINDOW_WIDTH;
+}
+
+/* Normally the window is deleted if it gets too small.
+   nodelete nonzero means do not do this.
+   (The caller should check later and do so if appropriate)  */
+static void
+set_window_pixsize (Lisp_Object window, int new_pixsize, int nodelete,
+		    int set_height)
+{
+  struct window *w = XWINDOW (window);
+  struct frame *f = XFRAME (w->frame);
+  struct window *c;
+  int old_pixsize = (set_height ? WINDOW_HEIGHT (w) : WINDOW_WIDTH (w));
+  Lisp_Object child, minor_kid, major_kid;
+  int minsize;
+  int line_size;
+  int defheight, defwidth;
+
+  /* #### This is very likely incorrect and instead the char_to_pixel_
+     functions should be called. */
+  default_face_height_and_width (window, &defheight, &defwidth);
+  line_size = (set_height ? defheight : defwidth);
+
+  check_min_window_sizes ();
+
+  minsize = (set_height ? window_min_height : window_min_width);
+  minsize *= line_size;
+
+  if (!nodelete
+      && !TOP_LEVEL_WINDOW_P (w)
+      && new_pixsize < minsize)
+    {
+      Fdelete_window (window, Qnil);
+      return;
+    }
+
+  SET_LAST_MODIFIED (w, 0);
+  SET_LAST_FACECHANGE (w);
+  MARK_FRAME_WINDOWS_STRUCTURE_CHANGED (f);	/* multiple windows affected */
+  if (set_height)
+    {
+      WINDOW_HEIGHT (w) = new_pixsize;
+      major_kid = w->vchild;
+      minor_kid = w->hchild;
+    }
+  else
+    {
+      WINDOW_WIDTH (w) = new_pixsize;
+      major_kid = w->hchild;
+      minor_kid = w->vchild;
+    }
+
+  if (!NILP (minor_kid))
+    {
+      for (child = minor_kid; !NILP (child); child = XWINDOW (child)->next)
+	{
+	  if (set_height)
+	    WINDOW_TOP (XWINDOW (child)) = WINDOW_TOP (w);
+	  else
+	    WINDOW_LEFT (XWINDOW (child)) = WINDOW_LEFT (w);
+
+	  set_window_pixsize (child, new_pixsize, nodelete, set_height);
+	}
+    }
+  else if (!NILP (major_kid))
+    {
+      int last_pos, last_old_pos, pos, old_pos, first;
+      int pixel_adj_left = new_pixsize - old_pixsize;
+      int div_val = old_pixsize << 1;
+
+      /*
+       * Previously we bailed out here if there was no size change.
+       * (pixel_adj_left == 0) But this broke toolbar updates.  If a
+       * toolbar appears or disappears, windows may not change size,
+       * but their top and left coordinates need to be updated.
+       *
+       * So we don't bail until after the loop below.
+       */
+
+      last_pos = first = (set_height ? WINDOW_TOP (w) : WINDOW_LEFT (w));
+      last_old_pos = 0;
+
+      for (child = major_kid; !NILP (child); child = c->next)
+	{
+	  c = XWINDOW (child);
+
+	  if (set_height)
+	    {
+	      old_pos = last_old_pos + WINDOW_HEIGHT (c);
+	      WINDOW_TOP (c) = last_pos;
+	    }
+	  else
+	    {
+	      old_pos = last_old_pos + WINDOW_WIDTH (c);
+	      WINDOW_LEFT (c) = last_pos;
+	    }
+
+	  pos = (((old_pos * new_pixsize) << 1) + old_pixsize) / div_val;
+	  /* All but the last window should have a height which is
+             a multiple of the default line height. */
+	  if (!NILP (c->next))
+	    pos = (pos / line_size) * line_size;
+
+	  /* Avoid confusion: don't delete child if it becomes too small */
+	  set_window_pixsize (child, pos + first - last_pos, 1, set_height);
+
+	  last_pos = pos + first;
+	  last_old_pos = old_pos;
+	}
+
+      /* Sometimes we may get called with our old size.  In that case
+         we don't need to do anything else. */
+      if (!pixel_adj_left)
+	return;
+
+      /* Now delete any children that became too small.  */
+      if (!nodelete)
+	for (child = major_kid; !NILP (child); child = XWINDOW (child)->next)
+	  {
+	    if (set_height)
+	      set_window_pixheight (child, WINDOW_HEIGHT (XWINDOW (child)), 0);
+	    else
+	      set_window_pixwidth (child, WINDOW_WIDTH (XWINDOW (child)), 0);
+	  }
+    }
+}
+
+/* Set the height of WINDOW and all its inferiors.  */
+void
+set_window_pixheight (Lisp_Object window, int new_pixheight, int nodelete)
+{
+  set_window_pixsize (window, new_pixheight, nodelete, 1);
+}
+
+/* Recursively set width of WINDOW and its inferiors. */
+void
+set_window_pixwidth (Lisp_Object window, int new_pixwidth, int nodelete)
+{
+  set_window_pixsize (window, new_pixwidth, nodelete, 0);
+}
+
+
+static int window_select_count;
+
+DEFUN ("set-window-buffer", Fset_window_buffer, 2, 2, 0, /*
+Make WINDOW display BUFFER as its contents.
+BUFFER can be a buffer or buffer name.
+*/
+       (window, buffer))
+{
+  Lisp_Object tem;
+  struct window *w = decode_window (window);
+
+  buffer = Fget_buffer (buffer);
+  CHECK_BUFFER (buffer);
+
+  if (!BUFFER_LIVE_P (XBUFFER (buffer)))
+    error ("Attempt to display deleted buffer");
+
+  tem = w->buffer;
+  if (NILP (tem))
+    error ("Window is deleted");
+
+  /* While this seems like a logical thing to do, it causes problems
+     because of saved window configurations.  It is possible for a
+     buffer to get restored into a window in which it is already being
+     displayed, but start and point are actually at completely
+     different locations.  So we let this function complete fully and
+     it will then make sure redisplay correctly updates things.
+
+     #### This is a kludge.  The correct approach is not to do this
+     but to fix set-window-configuration. */
+#if 0
+  else if (EQ (tem, buffer))
+    return Qnil;
+#endif
+  else if (! EQ (tem, Qt))	/* w->buffer is t when the window
+				   is first being set up.  */
+    {
+      if (!NILP (w->dedicated) && !EQ (tem, buffer))
+	error ("Window is dedicated to buffer %s",
+	       XSTRING_DATA (XBUFFER (tem)->name));
+
+      unshow_buffer (w);
+    }
+
+  w->buffer = buffer;
+  w->window_end_pos[CURRENT_DISP] = 0;
+  w->hscroll = 0;
+  w->modeline_hscroll = 0;
+  Fset_marker (w->pointm[CURRENT_DISP],
+	       make_int (BUF_PT (XBUFFER (buffer))),
+	       buffer);
+  set_marker_restricted (w->start[CURRENT_DISP],
+			 make_int (XBUFFER (buffer)->last_window_start),
+			 buffer);
+  Fset_marker (w->sb_point, w->start[CURRENT_DISP], buffer);
+  /* set start_at_line_beg correctly. GE */
+  w->start_at_line_beg = beginning_of_line_p (XBUFFER (buffer),
+					      marker_position (w->start[CURRENT_DISP]));
+  w->force_start = 0;           /* Lucid fix */
+  SET_LAST_MODIFIED (w, 1);
+  SET_LAST_FACECHANGE (w);
+  MARK_WINDOWS_CHANGED (w);
+  recompute_all_cached_specifiers_in_window (w);
+  if (EQ (window, Fselected_window (Qnil)))
+    {
+      Fset_buffer (buffer);
+    }
+  return Qnil;
+}
+
+DEFUN ("select-window", Fselect_window, 1, 2, 0, /*
+Select WINDOW.  Most editing will apply to WINDOW's buffer.
+The main editor command loop selects the buffer of the selected window
+before each command.
+
+With non-nil optional argument `norecord', do not modify the
+global or per-frame buffer ordering.
+*/
+       (window, norecord))
+{
+  struct window *w;
+  Lisp_Object old_selected_window = Fselected_window (Qnil);
+
+  CHECK_LIVE_WINDOW (window);
+  w = XWINDOW (window);
+
+  /* we have already caught dead-window errors */
+  if (!NILP (w->hchild) || !NILP (w->vchild))
+    error ("Trying to select non-leaf window");
+
+  w->use_time = make_int (++window_select_count);
+  if (EQ (window, old_selected_window))
+    return window;
+
+  /* deselect the old window, if it exists (it might not exist if
+     the selected device has no frames, which occurs at startup) */
+  if (!NILP (old_selected_window))
+    {
+      struct window *ow = XWINDOW (old_selected_window);
+
+      Fset_marker (ow->pointm[CURRENT_DISP],
+		   make_int (BUF_PT (XBUFFER (ow->buffer))),
+		   ow->buffer);
+
+      MARK_WINDOWS_CHANGED (ow);
+    }
+
+  /* now select the window's frame */
+  set_frame_selected_window (XFRAME (WINDOW_FRAME (w)), window);
+
+  select_frame_1 (WINDOW_FRAME (w));
+
+  /* also select the window's buffer */
+  if (NILP (norecord))
+    Frecord_buffer (w->buffer);
+  Fset_buffer (w->buffer);
+
+  /* Go to the point recorded in the window.
+     This is important when the buffer is in more
+     than one window.  It also matters when
+     redisplay_window has altered point after scrolling,
+     because it makes the change only in the window.  */
+  {
+    Bufpos new_point = marker_position (w->pointm[CURRENT_DISP]);
+    if (new_point < BUF_BEGV (current_buffer))
+      new_point = BUF_BEGV (current_buffer);
+    else if (new_point > BUF_ZV (current_buffer))
+      new_point = BUF_ZV (current_buffer);
+
+    BUF_SET_PT (current_buffer, new_point);
+  }
+
+  MARK_WINDOWS_CHANGED (w);
+
+  return window;
+}
+
+Lisp_Object
+display_buffer (Lisp_Object buffer, Lisp_Object not_this_window_p,
+		Lisp_Object override_frame)
+{
+  return call3 (Qdisplay_buffer, buffer, not_this_window_p, override_frame);
+}
+
+void
+temp_output_buffer_show (Lisp_Object buf, Lisp_Object same_frame)
+{
+  /* This function can GC */
+  Lisp_Object window;
+  struct window *w;
+  struct buffer *b = XBUFFER (buf);
+
+  BUF_SAVE_MODIFF (XBUFFER (buf)) = BUF_MODIFF (b);
+  widen_buffer (b, 0);
+  BUF_SET_PT (b, BUF_BEG (b));
+
+  if (!NILP (Vtemp_buffer_show_function))
+    call1 (Vtemp_buffer_show_function, buf);
+  else
+    {
+      window = display_buffer (buf, Qnil, same_frame);
+
+      if (!EQ (XWINDOW (window)->frame, Fselected_frame (Qnil)))
+	Fmake_frame_visible (WINDOW_FRAME (XWINDOW (window)));
+
+      Vminibuffer_scroll_window = window;
+      w = XWINDOW (window);
+      w->hscroll = 0;
+      w->modeline_hscroll = 0;
+      set_marker_restricted (w->start[CURRENT_DISP], make_int (1), buf);
+      set_marker_restricted (w->pointm[CURRENT_DISP], make_int (1), buf);
+      set_marker_restricted (w->sb_point, make_int (1), buf);
+
+      /* Run temp-buffer-show-hook, with the chosen window selected.  */
+      if (!preparing_for_armageddon)
+	{
+	  Lisp_Object tem;
+	  tem = Fboundp (Qtemp_buffer_show_hook);
+	  if (!NILP (tem))
+	    {
+	      tem = Fsymbol_value (Qtemp_buffer_show_hook);
+	      if (!NILP (tem))
+		{
+		  int count = specpdl_depth ();
+
+		  /* Select the window that was chosen, for running
+                     the hook.  */
+		  record_unwind_protect (save_window_excursion_unwind,
+					 Fcurrent_window_configuration (Qnil));
+
+		  Fselect_window (window, Qnil);
+		  run_hook (Qtemp_buffer_show_hook);
+		  unbind_to (count, Qnil);
+		}
+	    }
+	}
+    }
+}
+
+static void
+make_dummy_parent (Lisp_Object window)
+{
+  Lisp_Object new;
+  struct window *o = XWINDOW (window);
+  struct window *p = alloc_lcrecord_type (struct window, &lrecord_window);
+
+  XSETWINDOW (new, p);
+  copy_lcrecord (p, o);
+
+  /* Don't copy the pointers to the line start cache or the face
+     instances. */
+  p->line_start_cache = Dynarr_new (line_start_cache);
+  p->face_cachels     = Dynarr_new (face_cachel);
+  p->glyph_cachels    = Dynarr_new (glyph_cachel);
+
+  /* Put new into window structure in place of window */
+  replace_window (window, new);
+
+  o->next = Qnil;
+  o->prev = Qnil;
+  o->vchild = Qnil;
+  o->hchild = Qnil;
+  o->parent = new;
+
+  p->start[CURRENT_DISP] = Qnil;
+  p->start[DESIRED_DISP] = Qnil;
+  p->start[CMOTION_DISP] = Qnil;
+  p->pointm[CURRENT_DISP] = Qnil;
+  p->pointm[DESIRED_DISP] = Qnil;
+  p->pointm[CMOTION_DISP] = Qnil;
+  p->sb_point = Qnil;
+  p->buffer = Qnil;
+}
+
+DEFUN ("split-window", Fsplit_window, 0, 3, "", /*
+Split WINDOW, putting SIZE lines in the first of the pair.
+WINDOW defaults to selected one and SIZE to half its size.
+If optional third arg HOR-FLAG is non-nil, split side by side
+and put SIZE columns in the first of the pair.
+*/
+       (window, chsize, horflag))
+{
+  Lisp_Object new;
+  struct window *o, *p;
+  struct frame *f;
+  int size;
+  int psize;
+
+  if (NILP (window))
+    window = Fselected_window (Qnil);
+  else
+    CHECK_LIVE_WINDOW (window);
+
+  o = XWINDOW (window);
+  f = XFRAME (WINDOW_FRAME (o));
+
+  if (NILP (chsize))
+    {
+      if (!NILP (horflag))
+	/* In the new scheme, we are symmetric with respect to separators
+	   so there is no need to do weird things here. */
+	{
+	  psize = WINDOW_WIDTH (o) >> 1;
+	  size = window_pixel_width_to_char_width (o, psize, 0);
+        }
+      else
+        {
+	  psize = WINDOW_HEIGHT (o) >> 1;
+	  size = window_pixel_height_to_char_height (o, psize, 1);
+        }
+    }
+  else
+    {
+      CHECK_INT (chsize);
+      size = XINT (chsize);
+      if (!NILP (horflag))
+	psize = window_char_width_to_pixel_width (o, size, 0);
+      else
+	psize = window_char_height_to_pixel_height (o, size, 1);
+    }
+
+  if (MINI_WINDOW_P (o))
+    error ("Attempt to split minibuffer window");
+  else if (FRAME_NO_SPLIT_P (XFRAME (WINDOW_FRAME (o))))
+    error ("Attempt to split unsplittable frame");
+
+  check_min_window_sizes ();
+
+  if (NILP (horflag))
+    {
+      if (size < window_min_height)
+	error ("Window height %d too small (after splitting)", size);
+      if (size + window_min_height > window_char_height (o, 1))
+	error ("Window height %d too small (after splitting)",
+	       window_char_height (o, 1) - size);
+      if (NILP (o->parent)
+	  || NILP (XWINDOW (o->parent)->vchild))
+	{
+	  make_dummy_parent (window);
+	  reset_face_cachels (XWINDOW (window));
+	  new = o->parent;
+	  XWINDOW (new)->vchild = window;
+	  XFRAME (o->frame)->mirror_dirty = 1;
+	}
+    }
+  else
+    {
+      if (size < window_min_width)
+	error ("Window width %d too small (after splitting)", size);
+      if (size + window_min_width > window_char_width (o, 0))
+	error ("Window width %d too small (after splitting)",
+	       window_char_width (o, 0) - size);
+      if (NILP (o->parent)
+	  || NILP (XWINDOW (o->parent)->hchild))
+	{
+	  make_dummy_parent (window);
+	  reset_face_cachels (XWINDOW (window));
+	  new = o->parent;
+	  XWINDOW (new)->hchild = window;
+	  XFRAME (o->frame)->mirror_dirty = 1;
+	}
+    }
+
+  /* Now we know that window's parent is a vertical combination
+     if we are dividing vertically, or a horizontal combination
+     if we are making side-by-side windows */
+
+  MARK_FRAME_WINDOWS_STRUCTURE_CHANGED (f);
+  new = allocate_window ();
+  p = XWINDOW (new);
+
+  p->frame = o->frame;
+  p->next = o->next;
+  if (!NILP (p->next))
+    XWINDOW (p->next)->prev = new;
+  p->prev = window;
+  o->next = new;
+  p->parent = o->parent;
+  p->buffer = Qt;
+
+  reset_face_cachels (p);
+  reset_glyph_cachels (p);
+
+
+  /* Apportion the available frame space among the two new windows */
+
+  if (!NILP (horflag))
+    {
+      WINDOW_HEIGHT (p) = WINDOW_HEIGHT (o);
+      WINDOW_TOP (p) = WINDOW_TOP (o);
+      WINDOW_WIDTH (p) = WINDOW_WIDTH (o) - psize;
+      WINDOW_WIDTH (o) = psize;
+      WINDOW_LEFT (p) = WINDOW_LEFT (o) + psize;
+    }
+  else
+    {
+      WINDOW_LEFT (p) = WINDOW_LEFT (o);
+      WINDOW_WIDTH (p) = WINDOW_WIDTH (o);
+      WINDOW_HEIGHT (p) = WINDOW_HEIGHT (o) - psize;
+      WINDOW_HEIGHT (o) = psize;
+      WINDOW_TOP (p) = WINDOW_TOP (o) + psize;
+    }
+
+  XFRAME (p->frame)->mirror_dirty = 1;
+  /* do this last (after the window is completely initialized and
+     the mirror-dirty flag is set) so that specifier recomputation
+     caused as a result of this will work properly and not abort. */
+  Fset_window_buffer (new, o->buffer);
+  return new;
+}
+
+
+DEFUN ("enlarge-window", Fenlarge_window, 1, 3, "_p", /*
+Make the selected window N lines bigger.
+From program, optional second arg SIDE non-nil means grow sideways N columns,
+and optional third arg WINDOW specifies the window to change instead of the
+selected window.
+*/
+       (n, side, window))
+{
+  struct window *w = decode_window (window);
+  CHECK_INT (n);
+  change_window_height (w, XINT (n), !NILP (side), /* inpixels */ 0);
+  return Qnil;
+}
+
+DEFUN ("enlarge-window-pixels", Fenlarge_window_pixels, 1, 3, "_p", /*
+Make the selected window N pixels bigger.
+From program, optional second arg SIDE non-nil means grow sideways N pixels,
+and optional third arg WINDOW specifies the window to change instead of the
+selected window.
+*/
+       (n, side, window))
+{
+  struct window *w = decode_window (window);
+  CHECK_INT (n);
+  change_window_height (w, XINT (n), !NILP (side), /* inpixels */ 1);
+  return Qnil;
+}
+
+DEFUN ("shrink-window", Fshrink_window, 1, 3, "_p", /*
+Make the selected window N lines smaller.
+From program, optional second arg SIDE non-nil means shrink sideways N columns,
+and optional third arg WINDOW specifies the window to change instead of the
+selected window.
+*/
+       (n, side, window))
+{
+  CHECK_INT (n);
+  change_window_height (decode_window (window), -XINT (n), !NILP (side),
+                        /* inpixels */ 0);
+  return Qnil;
+}
+
+DEFUN ("shrink-window-pixels", Fshrink_window_pixels, 1, 3, "_p", /*
+Make the selected window N pixels smaller.
+From program, optional second arg SIDE non-nil means shrink sideways N pixels,
+and optional third arg WINDOW specifies the window to change instead of the
+selected window.
+*/
+       (n, side, window))
+{
+  CHECK_INT (n);
+  change_window_height (decode_window (window), -XINT (n), !NILP (side),
+                        /* inpixels */ 1);
+  return Qnil;
+}
+
+static int
+window_pixel_height (Lisp_Object window)
+{
+  return WINDOW_HEIGHT (XWINDOW (window));
+}
+
+static int
+window_pixel_height_to_char_height (struct window *w, int pixel_height,
+				    int include_gutters_p)
+{
+  int avail_height;
+  int defheight, defwidth;
+  int char_height;
+  Lisp_Object window;
+
+  XSETWINDOW (window, w);
+
+  avail_height = (pixel_height -
+		  (include_gutters_p ? 0 :
+		   window_top_gutter_height (w) +
+		   window_bottom_gutter_height (w)));
+
+  default_face_height_and_width (window, &defheight, &defwidth);
+
+  char_height = avail_height / defheight;
+
+  /* It's the calling function's responsibility to check these values
+     and make sure they're not out of range.
+
+     #### We need to go through the calling functions and actually
+     do this. */
+  return max (0, char_height);
+}
+
+static int
+window_char_height_to_pixel_height (struct window *w, int char_height,
+				    int include_gutters_p)
+{
+  int avail_height;
+  int defheight, defwidth;
+  int pixel_height;
+
+  Lisp_Object window;
+
+  XSETWINDOW (window, w);
+
+  default_face_height_and_width (window, &defheight, &defwidth);
+
+  avail_height = char_height * defheight;
+  pixel_height = (avail_height +
+		  (include_gutters_p ? 0 :
+		   window_top_gutter_height (w) +
+		   window_bottom_gutter_height (w)));
+
+  /* It's the calling function's responsibility to check these values
+     and make sure they're not out of range.
+
+     #### We need to go through the calling functions and actually
+     do this. */
+  return max (0, pixel_height);
+}
+
+/* Return number of default lines of text can fit in the window W.
+   If INCLUDE_GUTTERS_P is 1, include "gutter" space (modeline plus
+   horizontal scrollbar) in the space that is used for the calculation.
+   */
+int
+window_char_height (struct window *w, int include_gutters_p)
+{
+  return window_pixel_height_to_char_height (w, WINDOW_HEIGHT (w),
+					     include_gutters_p);
+}
+
+/*
+ * Return number of lines currently displayed in window w.  If
+ * end-of-buffer is displayed then the area below end-of-buffer is assume
+ * to be blank lines of default height.
+ * Does not include the modeline.
+ */
+int
+window_displayed_height (struct window *w)
+{
+  struct buffer *b = XBUFFER (w->buffer);
+  display_line_dynarr *dla = window_display_lines (w, CURRENT_DISP);
+  int num_lines;
+  Charcount end_pos = (BUF_Z (b) - w->window_end_pos[CURRENT_DISP] > BUF_ZV (b)
+		       ? -1
+		       : w->window_end_pos[CURRENT_DISP]);
+
+  if (!Dynarr_length (dla))
+    return window_char_height (w, 0);
+
+  num_lines = Dynarr_length (dla);
+
+  /* #### Document and assert somewhere that w->window_end_pos == -1
+     indicates that end-of-buffer is being displayed. */
+  if (end_pos == -1)
+    {
+      struct display_line *dl = Dynarr_atp (dla, 0);
+      int ypos1 = dl->ypos + dl->descent;
+      int ypos2 = WINDOW_TEXT_BOTTOM (w);
+      Lisp_Object window;
+      int defheight, defwidth;
+
+      XSETWINDOW (window, w);
+
+      if (dl->modeline)
+	{
+	  num_lines--;
+
+	  if (Dynarr_length (dla) == 1)
+	    ypos1 = WINDOW_TEXT_TOP (w);
+	  else
+	    {
+	      dl = Dynarr_atp (dla, Dynarr_length (dla) - 1);
+	      /* If this line is clipped then we know that there is no
+                 blank room between eob and the modeline.  If we are
+                 scrolling on clipped lines just know off the clipped
+                 line and return .*/
+	      if (scroll_on_clipped_lines && dl->clip)
+		return num_lines - 1;
+	      ypos1 = dl->ypos + dl->descent - dl->clip;
+	    }
+	}
+
+      default_face_height_and_width (window, &defheight, &defwidth);
+      /* #### This probably needs to know about the clipping area once a
+         final definition is decided on. */
+      num_lines += ((ypos2 - ypos1) / defheight);
+    }
+  else
+    {
+      if (num_lines > 1 && Dynarr_atp (dla, 0)->modeline)
+	num_lines--;
+
+      if (scroll_on_clipped_lines
+	  && Dynarr_atp (dla, Dynarr_length (dla) - 1)->clip)
+	num_lines--;
+    }
+
+  return num_lines;
+}
+
+static int
+window_pixel_width (Lisp_Object window)
+{
+  return WINDOW_WIDTH (XWINDOW (window));
+}
+
+static int
+window_pixel_width_to_char_width (struct window *w, int pixel_width,
+				  int include_margins_p)
+{
+  int avail_width;
+  int char_width;
+  int defheight, defwidth;
+  Lisp_Object window;
+
+  XSETWINDOW (window, w);
+
+  avail_width = (pixel_width -
+		 window_left_gutter_width (w, 0) -
+		 window_right_gutter_width (w, 0) -
+		 (include_margins_p ? 0 : window_left_margin_width (w)) -
+		 (include_margins_p ? 0 : window_right_margin_width (w)));
+
+  default_face_height_and_width (window, &defheight, &defwidth);
+
+  char_width = (avail_width / defwidth);
+
+  /* It's the calling function's responsibility to check these values
+     and make sure they're not out of range.
+
+     #### We need to go through the calling functions and actually
+     do this. */
+  return max (0, char_width);
+}
+
+static int
+window_char_width_to_pixel_width (struct window *w, int char_width,
+				  int include_margins_p)
+{
+  int avail_width;
+  int pixel_width;
+  int defheight, defwidth;
+  Lisp_Object window;
+
+  XSETWINDOW (window, w);
+
+  default_face_height_and_width (window, &defheight, &defwidth);
+
+  avail_width = char_width * defwidth;
+  pixel_width = (avail_width +
+		 window_left_gutter_width (w, 0) +
+		 window_right_gutter_width (w, 0) +
+		 (include_margins_p ? 0 : window_left_margin_width (w)) +
+		 (include_margins_p ? 0 : window_right_margin_width (w)));
+
+  /* It's the calling function's responsibility to check these values
+     and make sure they're not out of range.
+
+     #### We need to go through the calling functions and actually
+     do this. */
+  return max (0, pixel_width);
+}
+
+/* This returns the usable space which doesn't include space needed by
+   scrollbars or divider lines. */
+int
+window_char_width (struct window *w, int include_margins_p)
+{
+  return window_pixel_width_to_char_width (w, WINDOW_WIDTH (w),
+					   include_margins_p);
+}
+
+#define MINSIZE(w)						\
+  (widthflag							\
+   ? window_min_width * defwidth				\
+   : (defheight * (MINI_WINDOW_P (XWINDOW (w)) ? 1 : window_min_height)))
+
+#define CURBEG(w) \
+  *(widthflag ? (int *) &WINDOW_LEFT (w) : (int *) &WINDOW_TOP (w))
+
+#define CURSIZE(w) \
+  *(widthflag ? (int *) &WINDOW_WIDTH (w) : (int *) &WINDOW_HEIGHT (w))
+
+#define CURCHARSIZE(w) \
+  (widthflag ? window_char_width (w, 0) : window_char_height (w, 1))
+
+#define MINCHARSIZE(window) \
+  (widthflag ? window_min_width : MINI_WINDOW_P (XWINDOW (window)) \
+   ? 1 : window_min_height)
+
+/* Unlike set_window_pixheight, this function
+   also changes the heights of the siblings so as to
+   keep everything consistent. */
+
+static void
+change_window_height (struct window *win, int delta, int widthflag,
+                      int inpixels)
+{
+  Lisp_Object parent;
+  Lisp_Object window;
+  struct window *w;
+  struct frame *f;
+  int *sizep;
+  int (*sizefun) (Lisp_Object) = (widthflag
+				  ? window_pixel_width
+				  : window_pixel_height);
+  void (*setsizefun) (Lisp_Object, int, int) = (widthflag
+						? set_window_pixwidth
+						: set_window_pixheight);
+  int dim;
+  int defheight, defwidth;
+
+  if (delta == 0)
+    return;
+
+  check_min_window_sizes ();
+
+  XSETWINDOW (window, win);
+  f = XFRAME (win->frame);
+  if (EQ (window, FRAME_ROOT_WINDOW (f)))
+    error ("Won't change only window");
+
+  /* #### This is very likely incorrect and instead the char_to_pixel_
+     functions should be called. */
+  default_face_height_and_width (window, &defheight, &defwidth);
+
+  while (1)
+    {
+      w = XWINDOW (window);
+      parent = w->parent;
+      if (NILP (parent))
+	{
+	  if (widthflag)
+	    error ("No other window to side of this one");
+	  break;
+	}
+      if (widthflag
+          ? !NILP (XWINDOW (parent)->hchild)
+	  : !NILP (XWINDOW (parent)->vchild))
+	break;
+      window = parent;
+    }
+
+  sizep = &CURSIZE (w);
+  dim = CURCHARSIZE (w);
+
+  if ((inpixels  && (*sizep + delta) < MINSIZE (window)) ||
+      (!inpixels && (dim + delta) < MINCHARSIZE (window)))
+    {
+      if (MINI_WINDOW_P (XWINDOW (window)))
+	return;
+      else if (!NILP (parent))
+	{
+	  Fdelete_window (window, Qnil);
+	  return;
+	}
+    }
+
+  if (!inpixels)
+    delta *= (widthflag ? defwidth : defheight);
+
+  {
+    int maxdelta;
+
+    maxdelta = ((!NILP (parent))
+                ? (*sizefun) (parent) - *sizep
+		: ((!NILP (w->next))
+                   ? (*sizefun) (w->next) - MINSIZE (w->next)
+                   : ((!NILP (w->prev))
+                      ? (*sizefun) (w->prev) - MINSIZE (w->prev)
+                      /* This is a frame with only one window,
+                         a minibuffer-only or a minibufferless frame.  */
+                      : (delta = 0))));
+
+    if (delta > maxdelta)
+      /* This case traps trying to make the minibuffer
+	 the full frame, or make the only window aside from the
+	 minibuffer the full frame.  */
+      delta = maxdelta;
+
+    if (delta == 0)
+      return;
+
+#if 0 /* FSFmacs */
+    /* #### Chuck: is this correct? */
+    if (*sizep + delta < MINSIZE (window))
+      {
+	Fdelete_window (window);
+	return;
+      }
+#endif
+  }
+
+  if (!NILP (w->next) &&
+      (*sizefun) (w->next) - delta >= (int) MINSIZE (w->next))
+    {
+      CURBEG (XWINDOW (w->next)) += delta;
+      (*setsizefun) (w->next, (*sizefun) (w->next) - delta, 0);
+      (*setsizefun) (window, *sizep + delta, 0);
+    }
+  else if (!NILP (w->prev) &&
+	   (*sizefun) (w->prev) - delta >= (int) MINSIZE (w->prev))
+    {
+      (*setsizefun) (w->prev, (*sizefun) (w->prev) - delta, 0);
+      CURBEG (w) -= delta;
+      (*setsizefun) (window, *sizep + delta, 0);
+    }
+  else
+    {
+      int delta1;
+      int opht = (*sizefun) (parent);
+
+      /* If trying to grow this window to or beyond size of the parent,
+	 make delta1 so big that, on shrinking back down,
+	 all the siblings end up with less than one line and are deleted.  */
+      if (opht <= *sizep + delta)
+	delta1 = opht * opht * 2;
+      /* Otherwise, make delta1 just right so that if we add delta1
+	 lines to this window and to the parent, and then shrink
+	 the parent back to its original size, the new proportional
+	 size of this window will increase by delta.  */
+      else
+	delta1 = (delta * opht * 100) / ((opht - *sizep - delta) * 100);
+
+      /* Add delta1 lines or columns to this window, and to the parent,
+	 keeping things consistent while not affecting siblings.  */
+      CURSIZE (XWINDOW (parent)) = opht + delta1;
+      (*setsizefun) (window, *sizep + delta1, 0);
+
+      /* Squeeze out delta1 lines or columns from our parent,
+	 shrinking this window and siblings proportionately.
+	 This brings parent back to correct size.
+	 Delta1 was calculated so this makes this window the desired size,
+	 taking it all out of the siblings.  */
+      (*setsizefun) (parent, opht, 0);
+    }
+
+  SET_LAST_MODIFIED (w, 0);
+  SET_LAST_FACECHANGE (w);
+  MARK_FRAME_WINDOWS_STRUCTURE_CHANGED (f);
+  /* overkill maybe, but better to be correct */
+  MARK_FRAME_GUTTERS_CHANGED (f);
+}
+#undef MINSIZE
+#undef CURBEG
+#undef CURSIZE
+#undef CURCHARSIZE
+#undef MINCHARSIZE
+
+
+
+/* Scroll contents of window WINDOW up N lines. If N < (top line height /
+   average line height) then we just adjust the top clip.  */
+void
+window_scroll (Lisp_Object window, Lisp_Object n, int direction,
+	       Error_behavior errb)
+{
+  struct window *w = XWINDOW (window);
+  struct buffer *b = XBUFFER (w->buffer);
+  int selected = EQ (window, Fselected_window (Qnil));
+  int value = 0;
+  Lisp_Object point, tem;
+  display_line_dynarr *dla;
+  int fheight, fwidth, modeline = 0;
+  struct display_line* dl;
+
+  if (selected)
+    point = make_int (BUF_PT (b));
+  else
+    {
+      Bufpos pos = marker_position (w->pointm[CURRENT_DISP]);
+
+      if (pos < BUF_BEGV (b))
+	pos = BUF_BEGV (b);
+      else if (pos > BUF_ZV (b))
+	pos = BUF_ZV (b);
+
+      point = make_int (pos);
+    }
+
+  /* Always set force_start so that redisplay_window will run
+     the window-scroll-functions.  */
+  w->force_start = 1;
+
+  /* #### When the fuck does this happen?  I'm so glad that history has
+     completely documented the behavior of the scrolling functions under
+     all circumstances. */
+  tem = Fpos_visible_in_window_p (point, window);
+  if (NILP (tem))
+    {
+      Fvertical_motion (make_int (-window_char_height (w, 0) / 2),
+                        window, Qnil);
+      Fset_marker (w->start[CURRENT_DISP], point, w->buffer);
+      w->start_at_line_beg = beginning_of_line_p (b, XINT (point));
+      WINDOW_TEXT_TOP_CLIP (w) = 0;
+      MARK_WINDOWS_CHANGED (w);
+    }
+
+  if (!NILP (n))
+    {
+      if (EQ (n, Qminus))
+	direction *= -1;
+      else
+	{
+	  n = Fprefix_numeric_value (n);
+	  value = XINT (n) * direction;
+
+	  if (!value)
+	    return;	/* someone just made a pointless call */
+	}
+    }
+
+  /* If the user didn't specify how far to scroll then we have to figure it
+     out by ourselves. */
+  if (NILP (n) || EQ (n, Qminus))
+    {
+      /* Going forwards is easy.  If that is what we are doing then just
+	 set value and the section which handles the user specifying a
+	 positive value will work. */
+      if (direction == 1)
+	{
+	  value = window_displayed_height (w) - next_screen_context_lines;
+	  value = (value < 1 ? 1 : value);
+	}
+
+      /* Going backwards is hard.  We can't use the same loop used if the
+         user specified a negative value because we care about
+         next_screen_context_lines.  In a variable height world you don't
+         know how many lines above you can actually be displayed and still
+         have the context lines appear.  So we leave value set to 0 and add
+         a separate section to deal with this. */
+
+    }
+
+  if (direction == 1 && !value)
+    {
+      return;
+    }
+
+  /* Determine parameters to test for partial line scrolling with. */
+  dla = window_display_lines (w, CURRENT_DISP);
+
+  if (INTP (Vwindow_pixel_scroll_increment))
+    fheight = XINT (Vwindow_pixel_scroll_increment);
+  else if (!NILP (Vwindow_pixel_scroll_increment));
+    default_face_height_and_width (window, &fheight, &fwidth);
+  
+  if (Dynarr_length (dla) >= 1)
+    modeline = Dynarr_atp (dla, 0)->modeline;
+
+  dl = Dynarr_atp (dla, modeline);
+    
+  if (value > 0)
+    {
+      /* Go for partial display line scrolling. This just means bumping
+	 the clip by a reasonable amount and redisplaying, everything else
+	 remains unchanged. */
+      if (!NILP (Vwindow_pixel_scroll_increment)
+	  &&
+	  Dynarr_length (dla) >= (1 + modeline)
+	  &&
+	  (dl->ascent - dl->top_clip) - fheight * value > 0)
+	{
+	  WINDOW_TEXT_TOP_CLIP (w) += value * fheight;
+	  MARK_WINDOWS_CHANGED (w);
+	}
+      else
+	{
+	  int vtarget;
+	  Bufpos startp, old_start;
+	  
+	  if (WINDOW_TEXT_TOP_CLIP (w))
+	    {
+	      WINDOW_TEXT_TOP_CLIP (w) = 0;
+	      MARK_WINDOWS_CHANGED (w);
+	    }
+
+	  old_start = marker_position (w->start[CURRENT_DISP]);
+	  startp = vmotion (w, old_start, value, &vtarget);
+	  
+	  if (vtarget < value &&
+	      (w->window_end_pos[CURRENT_DISP] == -1
+	       || (BUF_Z (b) - w->window_end_pos[CURRENT_DISP] > BUF_ZV (b))))
+	    {
+	      maybe_signal_error (Qend_of_buffer, Qnil, Qwindow, errb);
+	      return;
+	    }
+	  else
+	    {
+	      set_marker_restricted (w->start[CURRENT_DISP], make_int (startp),
+				     w->buffer);
+	      w->force_start = 1;
+	      w->start_at_line_beg = beginning_of_line_p (b, startp);
+	      MARK_WINDOWS_CHANGED (w);
+	      
+	      if (!point_would_be_visible (w, startp, XINT (point)))
+		{
+		  if (selected)
+		    BUF_SET_PT (b, startp);
+		  else
+		    set_marker_restricted (w->pointm[CURRENT_DISP],
+					   make_int (startp),
+					   w->buffer);
+		}
+	    }
+	}
+    }
+  else if (value < 0)
+    {
+      /* Go for partial display line scrolling. This just means bumping
+	 the clip by a reasonable amount and redisplaying, everything else
+	 remains unchanged. */
+      if (!NILP (Vwindow_pixel_scroll_increment)
+	  &&
+	  Dynarr_length (dla) >= (1 + modeline)
+	  &&
+	  (dl->ascent - dl->top_clip) - fheight * value <
+	  (dl->ascent + dl->descent - dl->clip)
+	  &&
+	  WINDOW_TEXT_TOP_CLIP (w) + value * fheight > 0)
+	{
+	  WINDOW_TEXT_TOP_CLIP (w) += value * fheight;
+	  MARK_WINDOWS_CHANGED (w);
+	}
+      else
+	{
+	  int vtarget;
+	  Bufpos startp, old_start;
+	  
+	  if (WINDOW_TEXT_TOP_CLIP (w))
+	    {
+	      WINDOW_TEXT_TOP_CLIP (w) = 0;
+	      MARK_WINDOWS_CHANGED (w);
+	    }
+	      
+	  old_start = marker_position (w->start[CURRENT_DISP]);
+	  startp = vmotion (w, old_start, value, &vtarget);
+	  
+	  if (vtarget > value
+	      && marker_position (w->start[CURRENT_DISP]) == BUF_BEGV (b))
+	    {
+	      maybe_signal_error (Qbeginning_of_buffer, Qnil, Qwindow, errb);
+	      return;
+	    }
+	  else
+	    {
+	      set_marker_restricted (w->start[CURRENT_DISP], make_int (startp),
+				     w->buffer);
+	      w->force_start = 1;
+	      w->start_at_line_beg = beginning_of_line_p (b, startp);
+	      MARK_WINDOWS_CHANGED (w);
+	      
+	      if (!point_would_be_visible (w, startp, XINT (point)))
+		{
+		  Bufpos new_point;
+		  
+		  if (MINI_WINDOW_P (w))
+		    new_point = startp;
+		  else
+		    new_point = start_of_last_line (w, startp);
+		  
+		  if (selected)
+		    BUF_SET_PT (b, new_point);
+		  else
+		    set_marker_restricted (w->pointm[CURRENT_DISP],
+					   make_int (new_point),
+					   w->buffer);
+		}
+	    }
+	}
+    }
+  else	/* value == 0 && direction == -1 */
+    {
+      if (WINDOW_TEXT_TOP_CLIP (w))
+	{
+	  WINDOW_TEXT_TOP_CLIP (w) = 0;
+	  MARK_WINDOWS_CHANGED (w);
+	}
+      if (marker_position (w->start[CURRENT_DISP]) == BUF_BEGV (b))
+	{
+	  maybe_signal_error (Qbeginning_of_buffer, Qnil, Qwindow, errb);
+	  return;
+	}
+      else
+	{
+	  int vtarget;
+	  int movement = next_screen_context_lines - 1;
+	  Bufpos old_startp = marker_position (w->start[CURRENT_DISP]);
+	  Bufpos bottom = vmotion (w, old_startp, movement, &vtarget);
+	  Bufpos startp =
+	    start_with_point_on_display_line (w, bottom,
+					      -1 - (movement - vtarget));
+
+	  if (startp >= old_startp)
+	    startp = vmotion (w, old_startp, -1, NULL);
+
+	  set_marker_restricted (w->start[CURRENT_DISP], make_int (startp),
+				 w->buffer);
+	  w->force_start = 1;
+	  w->start_at_line_beg = beginning_of_line_p (b, startp);
+	  MARK_WINDOWS_CHANGED (w);
+
+	  if (!point_would_be_visible (w, startp, XINT (point)))
+	    {
+	      Bufpos new_point = start_of_last_line (w, startp);
+
+	      if (selected)
+		BUF_SET_PT (b, new_point);
+	      else
+		set_marker_restricted (w->pointm[CURRENT_DISP],
+				       make_int (new_point),
+				       w->buffer);
+	    }
+	}
+    }
+}
+
+DEFUN ("scroll-up", Fscroll_up, 0, 1, "_P", /*
+Scroll text of current window upward N lines; or near full screen if no arg.
+A near full screen is `next-screen-context-lines' less than a full screen.
+Negative N means scroll downward.
+When calling from a program, supply an integer as argument or nil.
+On attempt to scroll past end of buffer, `end-of-buffer' is signaled.
+On attempt to scroll past beginning of buffer, `beginning-of-buffer' is
+signaled.
+*/
+       (n))
+{
+  window_scroll (Fselected_window (Qnil), n, 1, ERROR_ME);
+  return Qnil;
+}
+
+DEFUN ("scroll-down", Fscroll_down, 0, 1, "_P", /*
+Scroll text of current window downward N lines; or near full screen if no arg.
+A near full screen is `next-screen-context-lines' less than a full screen.
+Negative N means scroll upward.
+When calling from a program, supply a number as argument or nil.
+On attempt to scroll past end of buffer, `end-of-buffer' is signaled.
+On attempt to scroll past beginning of buffer, `beginning-of-buffer' is
+signaled.
+*/
+       (n))
+{
+  window_scroll (Fselected_window (Qnil), n, -1, ERROR_ME);
+  return Qnil;
+}
+
+DEFUN ("other-window-for-scrolling", Fother_window_for_scrolling, 0, 0, 0, /*
+Return the other window for "other window scroll" commands.
+If in the minibuffer, `minibuffer-scroll-window' if non-nil
+specifies the window.
+If `other-window-scroll-buffer' is non-nil, a window
+showing that buffer is used.
+*/
+       ())
+{
+  Lisp_Object window;
+  Lisp_Object selected_window = Fselected_window (Qnil);
+
+  if (MINI_WINDOW_P (XWINDOW (selected_window))
+      && !NILP (Vminibuffer_scroll_window))
+    window = Vminibuffer_scroll_window;
+  /* If buffer is specified, scroll that buffer.  */
+  else if (!NILP (Vother_window_scroll_buffer))
+    {
+      window = Fget_buffer_window (Vother_window_scroll_buffer, Qnil, Qnil);
+      if (NILP (window))
+	window = display_buffer (Vother_window_scroll_buffer, Qt, Qnil);
+    }
+  else
+    {
+      /* Nothing specified; look for a neighboring window on the same
+	 frame.  */
+      window = Fnext_window (selected_window, Qnil, Qnil, Qnil);
+
+      if (EQ (window, selected_window))
+	/* That didn't get us anywhere; look for a window on another
+           visible frame.  */
+	do
+	  window = Fnext_window (window, Qnil, Qt, Qnil);
+	while (! FRAME_VISIBLE_P (XFRAME (WINDOW_FRAME (XWINDOW (window))))
+	       && ! EQ (window, selected_window));
+    }
+
+  CHECK_LIVE_WINDOW (window);
+
+  if (EQ (window, selected_window))
+    error ("There is no other window");
+
+  return window;
+ }
+
+DEFUN ("scroll-other-window", Fscroll_other_window, 0, 1, "_P", /*
+Scroll next window upward N lines; or near full frame if no arg.
+The next window is the one below the current one; or the one at the top
+if the current one is at the bottom.  Negative N means scroll downward.
+When calling from a program, supply a number as argument or nil.
+
+If in the minibuffer, `minibuffer-scroll-window' if non-nil
+specifies the window to scroll.
+If `other-window-scroll-buffer' is non-nil, scroll the window
+showing that buffer, popping the buffer up if necessary.
+*/
+       (n))
+{
+  window_scroll (Fother_window_for_scrolling (), n, 1, ERROR_ME);
+  return Qnil;
+}
+
+DEFUN ("scroll-left", Fscroll_left, 0, 1, "_P", /*
+Scroll selected window display N columns left.
+Default for N is window width minus 2.
+*/
+       (n))
+{
+  Lisp_Object window = Fselected_window (Qnil);
+  struct window *w = XWINDOW (window);
+  int count = (NILP (n) ?
+	       window_char_width (w, 0) - 2 :
+	       XINT (Fprefix_numeric_value (n)));
+
+  return Fset_window_hscroll (window, make_int (w->hscroll + count));
+}
+
+DEFUN ("scroll-right", Fscroll_right, 0, 1, "_P", /*
+Scroll selected window display N columns right.
+Default for N is window width minus 2.
+*/
+       (n))
+{
+  Lisp_Object window = Fselected_window (Qnil);
+  struct window *w = XWINDOW (window);
+  int count = (NILP (n) ?
+	       window_char_width (w, 0) - 2 :
+	       XINT (Fprefix_numeric_value (n)));
+
+  return Fset_window_hscroll (window, make_int (w->hscroll - count));
+}
+
+DEFUN ("center-to-window-line", Fcenter_to_window_line, 0, 2, "_P", /*
+Center point in WINDOW.  With N, put point on line N.
+The desired position of point is always relative to the window.
+If WINDOW is nil, the selected window is used.
+*/
+       (n, window))
+{
+  struct window *w = decode_window (window);
+  struct buffer *b = XBUFFER (w->buffer);
+  Bufpos opoint = BUF_PT (b);
+  Bufpos startp;
+
+  if (NILP (n))
+    startp = start_with_line_at_pixpos (w, opoint, window_half_pixpos (w));
+  else
+    {
+      n = Fprefix_numeric_value (n);
+      CHECK_INT (n);
+      startp = start_with_point_on_display_line (w, opoint, XINT (n));
+    }
+
+  Fset_marker (w->start[CURRENT_DISP], make_int (startp), w->buffer);
+
+  w->start_at_line_beg = beginning_of_line_p (b, startp);
+  w->force_start = 1;
+  MARK_WINDOWS_CHANGED (w);
+  return Qnil;
+}
+
+DEFUN ("move-to-window-line", Fmove_to_window_line, 1, 2, "_P", /*
+Position point relative to WINDOW.
+With no argument, position text at center of window.
+An argument specifies window line; zero means top of window,
+negative means relative to bottom of window.
+If WINDOW is nil, the selected window is used.
+*/
+       (arg, window))
+{
+  struct window *w;
+  struct buffer *b;
+  int height;
+  Bufpos start, new_point;
+  int selected;
+
+  /* Don't use decode_window() because we need the new value of
+     WINDOW.  */
+  if (NILP (window))
+    window = Fselected_window (Qnil);
+  else
+    CHECK_LIVE_WINDOW (window);
+  w = XWINDOW (window);
+  b = XBUFFER (w->buffer);
+
+  height = window_displayed_height (w);
+  selected = EQ (window, Fselected_window (w->frame));
+
+  if (NILP (arg))
+    {
+      int retval;
+
+      if (XINT (w->last_modified[CURRENT_DISP]) >= BUF_MODIFF (b)
+	  && XINT (w->last_facechange[CURRENT_DISP]) >= BUF_FACECHANGE (b))
+	{
+	  new_point = point_at_center (w, CURRENT_DISP, 0, 0);
+
+	  if (selected)
+	    BUF_SET_PT (b, new_point);
+	  else
+	    Fset_window_point (window, make_int (new_point));
+
+	  retval = line_at_center (w, CURRENT_DISP, 0, 0);
+	}
+      else
+	{
+	  start = marker_position (w->start[CURRENT_DISP]);
+	  if (start < BUF_BEGV (b))
+	    start = BUF_BEGV (b);
+	  else if (start > BUF_ZV (b))
+	    start = BUF_ZV (b);
+
+	  if (selected)
+	    new_point = BUF_PT (b);
+	  else
+	    new_point = marker_position (w->pointm[CURRENT_DISP]);
+
+	  new_point = point_at_center (w, CMOTION_DISP, start, BUF_PT (b));
+
+	  if (selected)
+	    BUF_SET_PT (b, new_point);
+	  else
+	    Fset_window_point (window, make_int (new_point));
+
+	  retval = line_at_center (w, CMOTION_DISP, start, BUF_PT (b));
+	}
+
+      return make_int (retval);
+    }
+  else
+    {
+      /* #### Is this going to work right when at eob? */
+      arg = Fprefix_numeric_value (arg);
+      if (XINT (arg) < 0)
+	XSETINT (arg, XINT (arg) + height);
+    }
+
+  start = marker_position (w->start[CURRENT_DISP]);
+  if (start < BUF_BEGV (b) || start > BUF_ZV (b))
+    {
+      if (selected)
+	new_point = BUF_PT (b);
+      else
+	new_point = marker_position (w->pointm[CURRENT_DISP]);
+
+      new_point = vmotion (XWINDOW (window), new_point, -height / 2, 0);
+
+      if (selected)
+	BUF_SET_PT (b, new_point);
+      else
+	Fset_window_point (window, make_int (new_point));
+
+      Fset_marker (w->start[CURRENT_DISP], make_int (new_point),
+		   w->buffer);
+      w->start_at_line_beg = beginning_of_line_p (b, new_point);
+      w->force_start = 1;
+    }
+  else
+    {
+      if (selected)
+	BUF_SET_PT (b, start);
+      else
+	Fset_window_point (window, make_int (start));
+    }
+
+  if (selected)
+    return Fvertical_motion (arg, window, Qnil);
+  else
+    {
+      int vpos;
+      new_point = vmotion (XWINDOW (window),
+			   marker_position (w->pointm[CURRENT_DISP]),
+			   XINT (arg), &vpos);
+      Fset_window_point (window, make_int (new_point));
+      return make_int (vpos);
+    }
+}
+
+
+static int
+map_windows_1 (Lisp_Object window,
+	       int (*mapfun) (struct window *w, void *closure),
+	       void *closure)
+{
+  for (; !NILP (window); window = XWINDOW (window)->next)
+    {
+      int retval;
+      struct window *w = XWINDOW (window);
+
+      if (!NILP (w->vchild))
+	retval = map_windows_1 (w->vchild, mapfun, closure);
+      else if (!NILP (w->hchild))
+	retval = map_windows_1 (w->hchild, mapfun, closure);
+      else
+	retval = (mapfun) (w, closure);
+
+      if (retval)
+	return retval;
+    }
+
+  return 0;
+}
+
+/* Map MAPFUN over the windows in F.  CLOSURE is passed to each
+   invocation of MAPFUN.  If any invocation of MAPFUN returns
+   non-zero, the mapping is halted.  Otherwise, map_windows() maps
+   over all windows in F.
+
+   If MAPFUN creates or deletes windows, the behavior is undefined.  */
+
+int
+map_windows (struct frame *f, int (*mapfun) (struct window *w, void *closure),
+	     void *closure)
+{
+  if (f)
+    return map_windows_1 (FRAME_ROOT_WINDOW (f), mapfun, closure);
+  else
+    {
+      Lisp_Object frmcons, devcons, concons;
+
+      FRAME_LOOP_NO_BREAK(frmcons, devcons, concons)
+	{
+	  int v = map_windows_1 (FRAME_ROOT_WINDOW (XFRAME (XCAR (frmcons))),
+				 mapfun, closure);
+	  if (v)
+	    return v;
+	}
+    }
+
+  return 0;
+}
+
+
+static void
+modeline_shadow_thickness_changed (Lisp_Object specifier, struct window *w,
+				   Lisp_Object oldval)
+{
+  w->shadow_thickness_changed = 1;
+  MARK_WINDOWS_CHANGED (w);
+}
+
+static void
+vertical_divider_changed_in_window (Lisp_Object specifier,
+				    struct window *w,
+				    Lisp_Object oldval)
+{
+  MARK_WINDOWS_CHANGED (w);
+  MARK_FRAME_WINDOWS_STRUCTURE_CHANGED (XFRAME (WINDOW_FRAME (w)));
+}
+
+/* also used in scrollbar.c */
+void
+some_window_value_changed (Lisp_Object specifier, struct window *w,
+			   Lisp_Object oldval)
+{
+  MARK_WINDOWS_CHANGED (w);
+}
+
+#ifdef MEMORY_USAGE_STATS
+
+struct window_stats
+{
+  int face;
+  int glyph;
+#ifdef HAVE_SCROLLBARS
+  int scrollbar;
+#endif
+  int line_start;
+  int other_redisplay;
+  int other;
+};
+
+static void
+compute_window_mirror_usage (struct window_mirror *mir,
+			     struct window_stats *stats,
+			     struct overhead_stats *ovstats)
+{
+  if (!mir)
+    return;
+  stats->other += malloced_storage_size (mir, sizeof (struct window_mirror),
+					 ovstats);
+#ifdef HAVE_SCROLLBARS
+  {
+    struct device *d = XDEVICE (FRAME_DEVICE (mir->frame));
+
+    stats->scrollbar +=
+      compute_scrollbar_instance_usage (d, mir->scrollbar_vertical_instance,
+					ovstats);
+    stats->scrollbar +=
+      compute_scrollbar_instance_usage (d, mir->scrollbar_horizontal_instance,
+					ovstats);
+  }
+#endif /* HAVE_SCROLLBARS */
+  stats->other_redisplay +=
+    compute_display_line_dynarr_usage (mir->current_display_lines, ovstats);
+  stats->other_redisplay +=
+    compute_display_line_dynarr_usage (mir->desired_display_lines, ovstats);
+}
+
+static void
+compute_window_usage (struct window *w, struct window_stats *stats,
+		      struct overhead_stats *ovstats)
+{
+  xzero (*stats);
+  stats->other += malloced_storage_size (w, sizeof (struct window), ovstats);
+  stats->face += compute_face_cachel_usage (w->face_cachels, ovstats);
+  stats->glyph += compute_glyph_cachel_usage (w->glyph_cachels, ovstats);
+  stats->line_start +=
+    compute_line_start_cache_dynarr_usage (w->line_start_cache, ovstats);
+  compute_window_mirror_usage (find_window_mirror (w), stats, ovstats);
+}
+
+DEFUN ("window-memory-usage", Fwindow_memory_usage, 1, 1, 0, /*
+Return stats about the memory usage of window WINDOW.
+The values returned are in the form of an alist of usage types and byte
+counts.  The byte counts attempt to encompass all the memory used
+by the window (separate from the memory logically associated with a
+buffer or frame), including internal structures and any malloc()
+overhead associated with them.  In practice, the byte counts are
+underestimated because certain memory usage is very hard to determine
+\(e.g. the amount of memory used inside the Xt library or inside the
+X server) and because there is other stuff that might logically
+be associated with a window, buffer, or frame (e.g. window configurations,
+glyphs) but should not obviously be included in the usage counts.
+
+Multiple slices of the total memory usage may be returned, separated
+by a nil.  Each slice represents a particular view of the memory, a
+particular way of partitioning it into groups.  Within a slice, there
+is no overlap between the groups of memory, and each slice collectively
+represents all the memory concerned.
+*/
+       (window))
+{
+  struct window_stats stats;
+  struct overhead_stats ovstats;
+  Lisp_Object val = Qnil;
+
+  CHECK_WINDOW (window); /* dead windows should be allowed, no? */
+  xzero (ovstats);
+  compute_window_usage (XWINDOW (window), &stats, &ovstats);
+
+  val = acons (Qface_cache,          make_int (stats.face),              val);
+  val = acons (Qglyph_cache,         make_int (stats.glyph),             val);
+#ifdef HAVE_SCROLLBARS
+  val = acons (Qscrollbar_instances, make_int (stats.scrollbar),         val);
+#endif
+  val = acons (Qline_start_cache,    make_int (stats.line_start),        val);
+  val = acons (Qother_redisplay,     make_int (stats.other_redisplay),   val);
+  val = acons (Qother,               make_int (stats.other),             val);
+  val = Fcons (Qnil, val);
+  val = acons (Qactually_requested,  make_int (ovstats.was_requested),   val);
+  val = acons (Qmalloc_overhead,     make_int (ovstats.malloc_overhead), val);
+  val = acons (Qdynarr_overhead,     make_int (ovstats.dynarr_overhead), val);
+
+  return Fnreverse (val);
+}
+
+#endif /* MEMORY_USAGE_STATS */
+
+
+/************************************************************************/
+/*                         Window configurations                        */
+/************************************************************************/
+
+/* #### This window configuration stuff has had serious bugs lurking in it
+   for years; it would be a -huge- win if this was reimplemented in lisp.
+ */
+
+/* If you add anything to this structure make sure saved_window_equal
+   knows about it. */
+struct saved_window
+{
+  Lisp_Object window;         /* window */
+  Lisp_Object buffer;         /* buffer */
+  Lisp_Object start;          /* copied marker */
+  Lisp_Object pointm;         /* copied marker */
+  Lisp_Object sb_point;	      /* copied marker */
+  Lisp_Object mark;           /* copied marker */
+  int pixel_left;
+  int pixel_top;
+  int pixel_width;
+  int pixel_height;
+  int hscroll;
+  int modeline_hscroll;
+  int parent_index;           /* index into saved_windows */
+  int prev_index;             /* index into saved_windows */
+  char start_at_line_beg; /* boolean */
+
+#define WINDOW_SLOT_DECLARATION
+#define WINDOW_SLOT(slot, compare) Lisp_Object slot
+#include "winslots.h"
+};
+
+/* If you add anything to this structure make sure window_config_equal
+   knows about it. */
+struct window_config
+{
+  struct lcrecord_header header;
+  /*  int frame_width; No longer needed, JV
+      int frame_height; */
+#if 0 /* FSFmacs */
+  Lisp_Object selected_frame;
+#endif
+  Lisp_Object current_window;
+  Lisp_Object current_buffer;
+  Lisp_Object minibuffer_scroll_window;
+  Lisp_Object root_window;
+  int minibuf_height; /* 0 = no minibuffer, <0, size in lines, >0 in pixels */
+  /* Record the values of window-min-width and window-min-height
+     so that window sizes remain consistent with them.  */
+  int min_width, min_height;
+  int saved_windows_count;
+  /* Zero-sized arrays aren't ANSI C */
+  struct saved_window saved_windows[1];
+};
+
+#define SAVED_WINDOW_N(conf, n) (&((conf)->saved_windows[(n)]))
+#define XWINDOW_CONFIGURATION(x) XRECORD (x, window_configuration, struct window_config)
+#define XSETWINDOW_CONFIGURATION(x, p) XSETRECORD (x, p, window_configuration)
+#define WINDOW_CONFIGURATIONP(x) RECORDP (x, window_configuration)
+#define GC_WINDOW_CONFIGURATIONP(x) GC_RECORDP (x, window_configuration)
+#define CHECK_WINDOW_CONFIGURATION(x) CHECK_RECORD (x, window_configuration)
+
+static Lisp_Object
+mark_window_config (Lisp_Object obj)
+{
+  struct window_config *config = XWINDOW_CONFIGURATION (obj);
+  int i;
+  mark_object (config->current_window);
+  mark_object (config->current_buffer);
+  mark_object (config->minibuffer_scroll_window);
+  mark_object (config->root_window);
+
+  for (i = 0; i < config->saved_windows_count; i++)
+    {
+      struct saved_window *s = SAVED_WINDOW_N (config, i);
+      mark_object (s->window);
+      mark_object (s->buffer);
+      mark_object (s->start);
+      mark_object (s->pointm);
+      mark_object (s->sb_point);
+      mark_object (s->mark);
+#if 0
+      /* #### This looked like this. I do not see why specifier cached
+	 values should not be marked, as such specifiers as toolbars
+	 might have GC-able instances. Freed configs are not marked,
+	 aren't they?  -- kkm */
+      mark_object (s->dedicated);
+#else
+#define WINDOW_SLOT(slot, compare) mark_object (s->slot)
+#include "winslots.h"
+#endif
+    }
+  return Qnil;
+}
+
+static size_t
+sizeof_window_config_for_n_windows (int n)
+{
+  return (sizeof (struct window_config) +
+	  /* n - 1 because zero-sized arrays aren't ANSI C */
+	  (n - 1) *sizeof (struct saved_window));
+}
+
+static size_t
+sizeof_window_config (CONST void *h)
+{
+  CONST struct window_config *c = (CONST struct window_config *) h;
+  return sizeof_window_config_for_n_windows (c->saved_windows_count);
+}
+
+static void
+print_window_config (Lisp_Object obj, Lisp_Object printcharfun, int escapeflag)
+{
+  struct window_config *config = XWINDOW_CONFIGURATION (obj);
+  char buf[200];
+  if (print_readably)
+    error ("printing unreadable object #<window-configuration 0x%x>",
+           config->header.uid);
+  write_c_string ("#<window-configuration ", printcharfun);
+  sprintf (buf, "0x%x>", config->header.uid);
+  write_c_string (buf, printcharfun);
+}
+
+DEFINE_LRECORD_SEQUENCE_IMPLEMENTATION ("window-configuration",
+					window_configuration,
+					mark_window_config,
+					print_window_config,
+					0, 0, 0, 0, sizeof_window_config,
+					struct window_config);
+
+
+/* Returns a boolean indicating whether the two saved windows are
+   identical. */
+static int
+saved_window_equal (struct saved_window *win1, struct saved_window *win2)
+{
+#define WINDOW_SLOT(slot, compare)		\
+  if (!compare (win1->slot, win2->slot))	\
+    return 0;
+#include "winslots.h"
+
+  return
+    EQ (win1->window, win2->window) &&
+    EQ (win1->buffer, win2->buffer) &&
+    internal_equal (win1->start,    win2->start, 0) &&
+    internal_equal (win1->pointm,   win2->pointm, 0) &&
+    internal_equal (win1->sb_point, win2->sb_point, 0) &&
+    internal_equal (win1->mark,     win2->mark, 0) &&
+    win1->pixel_left   == win2->pixel_left &&
+    win1->pixel_top    == win2->pixel_top &&
+    win1->pixel_width  == win2->pixel_width &&
+    win1->pixel_height == win2->pixel_height &&
+    win1->hscroll      == win2->hscroll &&
+    win1->modeline_hscroll == win2->modeline_hscroll &&
+    win1->parent_index == win2->parent_index &&
+    win1->prev_index   == win2->prev_index &&
+    win1->start_at_line_beg == win2->start_at_line_beg;
+}
+
+/* Returns a boolean indicating whether the two given configurations
+   are identical. */
+static int
+window_config_equal (Lisp_Object conf1, Lisp_Object conf2)
+{
+  struct window_config *fig1, *fig2;
+  int i;
+
+  /* First check if they are truly the same. */
+  if (EQ (conf1, conf2))
+    return 1;
+
+  fig1 = XWINDOW_CONFIGURATION (conf1);
+  fig2 = XWINDOW_CONFIGURATION (conf2);
+
+  if (!((fig1->saved_windows_count == fig2->saved_windows_count) &&
+	EQ (fig1->current_window,	    fig2->current_window) &&
+	EQ (fig1->current_buffer,	    fig2->current_buffer) &&
+	EQ (fig1->root_window,		    fig2->root_window) &&
+	EQ (fig1->minibuffer_scroll_window, fig2->minibuffer_scroll_window)))
+	/* &&
+	fig1->frame_width  == fig2->frame_width &&
+	fig1->frame_height == fig2->frame_height)) */
+    return 0;
+
+  for (i = 0; i < fig1->saved_windows_count; i++)
+    {
+      if (!saved_window_equal (SAVED_WINDOW_N (fig1, i),
+			       SAVED_WINDOW_N (fig2, i)))
+	return 0;
+    }
+
+  return 1;
+}
+
+DEFUN ("window-configuration-p", Fwindow_configuration_p, 1, 1, 0, /*
+Return t if OBJECT is a window-configuration object.
+*/
+       (obj))
+{
+  return WINDOW_CONFIGURATIONP (obj) ? Qt : Qnil;
+}
+
+static int
+mark_windows_in_use_closure (struct window *w, void *closure)
+{
+  int mark = *(int *)closure;
+  w->config_mark = mark;
+  return 0;
+}
+
+static void
+mark_windows_in_use (struct frame *f, int mark)
+{
+  map_windows (f, mark_windows_in_use_closure, &mark);
+}
+
+/* Lisp_Object return value so it can be used in record_unwind_protect() */
+static Lisp_Object
+free_window_configuration (Lisp_Object window_config)
+{
+  int i;
+  struct window_config *config = XWINDOW_CONFIGURATION (window_config);
+
+  /* Free all the markers.  It's not completely necessary that
+     we do this (window configs sitting in a free list aren't
+     marked normally so the markers wouldn't be marked anyway)
+     but it's more efficient. */
+  for (i = 0; i < config->saved_windows_count; i++)
+    {
+      struct saved_window *p = SAVED_WINDOW_N (config, i);
+
+      if (!NILP (p->pointm))
+	{
+	  free_marker (XMARKER (p->pointm));
+	  p->pointm = Qnil;
+	}
+      if (!NILP (p->start))
+	{
+	  free_marker (XMARKER (p->start));
+	  p->start = Qnil;
+	}
+      if (!NILP (p->sb_point))
+	{
+	  free_marker (XMARKER (p->sb_point));
+	  p->sb_point = Qnil;
+	}
+      if (!NILP (p->mark))
+	{
+	  free_marker (XMARKER (p->mark));
+	  p->mark = Qnil;
+	}
+    }
+
+  if (config->saved_windows_count <= countof (Vwindow_configuration_free_list))
+    free_managed_lcrecord (Vwindow_configuration_free_list
+			   [config->saved_windows_count - 1],
+			   window_config);
+
+  return Qnil;
+}
+
+DEFUN ("set-window-configuration", Fset_window_configuration, 1, 1, 0, /*
+Set the configuration of windows and buffers as specified by CONFIGURATION.
+CONFIGURATION must be a value previously returned
+by `current-window-configuration' (which see).
+*/
+       (configuration))
+{
+  struct window *w;
+  struct window_config *config;
+  struct saved_window *p;
+  Lisp_Object new_current_buffer;
+  int k;
+  Lisp_Object frame;
+  struct frame *f;
+  struct gcpro gcpro1;
+  Lisp_Object old_window_config;
+  /*  int previous_frame_height;
+      int previous_frame_width;*/
+  int previous_pixel_top;
+  int previous_pixel_height;
+  int previous_pixel_left;
+  int previous_pixel_width;
+  int previous_minibuf_height, previous_minibuf_top,previous_minibuf_width;
+  int real_font_height;
+  int converted_minibuf_height,target_minibuf_height; 
+  int specpdl_count = specpdl_depth ();
+
+  GCPRO1 (configuration);
+
+  CHECK_WINDOW_CONFIGURATION (configuration);
+  config = XWINDOW_CONFIGURATION (configuration);
+
+  frame = XWINDOW (SAVED_WINDOW_N (config, 0)->window)->frame;
+  f = XFRAME (frame);
+
+  /* Do not signal an error here if the frame was deleted.  There are
+     reasonable cases where we could get here with a deleted frame and
+     just want to do close to nothing instead. */
+
+  if (FRAME_LIVE_P (f))
+    {
+      /* restore the frame characteristics */
+
+      new_current_buffer = config->current_buffer;
+      if (!BUFFER_LIVE_P (XBUFFER (new_current_buffer)))
+	new_current_buffer = Qnil;
+
+      /*
+       * Assumed precondition:  w->config_mark = 0 for all w
+       * This procedure should ensure this is true by the time it exits
+       * to ensure the precondition for future calls.
+       *
+       * We use w->config_mark to know whether we're modifying a
+       * window that is currently visible on the frame (#### we
+       * should just be able to check whether the window is dead
+       * or not, but this way is safer?).  As we process each
+       * window, we set its config_mark to 0.  At the end, we
+       * go through all the windows that used to be on the frame,
+       * set each one's config_mark to 0 (to maintain the
+       * assumed precondition) and delete each one that's no
+       * longer in use.
+       *
+       * #### Using a window-configuration to keep track of
+       * the current windows is wasteful.  All we need is the
+       * list of windows, so we could just use a dynarr.
+       */
+      old_window_config = Fcurrent_window_configuration (frame);
+
+      /* If the new configuration is already equal to the old, then stop
+	 right here.  This saves the work below and it also saves
+	 triggering a full redisplay of this window.  This is a huge win
+	 when using the mouse since the mode motion code uses
+	 save-window-excursion extensively but will rarely cause the
+	 configuration to actually change. */
+      if (window_config_equal (configuration, old_window_config))
+	{
+	  free_window_configuration (old_window_config);
+	  UNGCPRO;
+	  return Qnil;
+	}
+
+      /* We can't quit or even check for quit because that may cause
+	 investigation of the frame state, which may crash if the frame is
+	 in an inconsistent state. */
+      begin_dont_check_for_quit ();
+      record_unwind_protect (free_window_configuration, old_window_config);
+
+      mark_windows_in_use (f, 1);
+
+#if 0
+      /* JV: This is bogus,
+	 First of all, the units are inconsistent. The frame sizes are measured
+	 in characters but the window sizes are stored in pixels. So if a 
+	 font size change happened between saving and restoring, the
+	 frame "sizes" maybe equal but the windows still should be
+	 resized. This is tickled alot by the new "character size
+	 stays constant" policy in 21.0. It leads to very wierd
+	 glitches (and possibly craches when asserts are tickled).
+
+	 Just changing the units doens't help because changing the
+	 toolbar configuration can also change the pixel positions.
+	 Luckily there is a much simpler way of doing this, see below.
+       */
+      previous_frame_width = FRAME_WIDTH (f);
+      previous_frame_height = FRAME_HEIGHT (f);
+      /* If the frame has been resized since this window configuration was
+	 made, we change the frame to the size specified in the
+	 configuration, restore the configuration, and then resize it
+	 back.  We keep track of the prevailing height in these variables.  */
+      if (config->frame_height != FRAME_HEIGHT (f)
+	  || config->frame_width != FRAME_WIDTH (f))
+	change_frame_size (f, config->frame_height, config->frame_width, 0);
+#endif
+      
+      previous_pixel_top = XWINDOW (FRAME_ROOT_WINDOW (f))->pixel_top;
+      previous_pixel_height = XWINDOW (FRAME_ROOT_WINDOW (f))->pixel_height;
+      previous_pixel_left = XWINDOW (FRAME_ROOT_WINDOW (f))->pixel_left;
+      previous_pixel_width = XWINDOW (FRAME_ROOT_WINDOW (f))->pixel_width;
+
+      /* remember some properties of the minibuffer */
+
+      default_face_height_and_width (frame, &real_font_height, 0);
+      assert(real_font_height > 0);
+  
+      if (FRAME_HAS_MINIBUF_P (f) && ! FRAME_MINIBUF_ONLY_P (f))
+	{
+	  previous_minibuf_height
+	    = XWINDOW(FRAME_MINIBUF_WINDOW(f))->pixel_height;
+	  previous_minibuf_top
+	    = XWINDOW(FRAME_MINIBUF_WINDOW(f))->pixel_top;
+	  previous_minibuf_width
+	    = XWINDOW(FRAME_MINIBUF_WINDOW(f))->pixel_width;
+	}
+      else
+	{
+	  previous_minibuf_height = 0;
+	  previous_minibuf_width = 0;
+	}
+      converted_minibuf_height =
+	(previous_minibuf_height % real_font_height) == 0 ?
+	- (previous_minibuf_height / real_font_height ) :    /* lines */
+	    previous_minibuf_height;   /* pixels */
+           
+      /* Temporarily avoid any problems with windows that are smaller
+	 than they are supposed to be.  */
+      window_min_height = 1;
+      window_min_width = 1;
+
+      /* OK, now restore all the windows in the window config.
+	 This may involve "undeleting" windows, since the
+	 windows in the window config may be deleted.
+	 */
+      for (k = 0; k < config->saved_windows_count; k++)
+	{
+	  p = SAVED_WINDOW_N (config, k);
+	  w = XWINDOW (p->window);
+	  w->next = Qnil;
+
+	  /* The window might be dead.  In this case, its redisplay
+	     structures were freed, so we need to reallocate them. */
+	  if (!w->face_cachels)
+	    {
+	      w->face_cachels = Dynarr_new (face_cachel);
+	      reset_face_cachels (w);
+	    }
+	  if (!w->glyph_cachels)
+	    w->glyph_cachels = Dynarr_new (glyph_cachel);
+	  if (!w->line_start_cache)
+	    w->line_start_cache = Dynarr_new (line_start_cache);
+	  w->dead = 0;
+
+	  if (p->parent_index >= 0)
+	    w->parent = SAVED_WINDOW_N (config, p->parent_index)->window;
+	  else
+	    w->parent = Qnil;
+
+	  if (p->prev_index >= 0)
+	    {
+	      w->prev = SAVED_WINDOW_N (config, p->prev_index)->window;
+
+	      /* This is true for a minibuffer-only frame. */
+	      if (!NILP (w->mini_p) && EQ (w->prev, p->window))
+		w->next = Qnil;
+	      else
+		XWINDOW (w->prev)->next = p->window;
+	    }
+	  else
+	    {
+	      w->prev = Qnil;
+	      if (!NILP (w->parent))
+		{
+		  if (WINDOW_WIDTH (p) == WINDOW_WIDTH (XWINDOW (w->parent)))
+		    {
+		      XWINDOW (w->parent)->vchild = p->window;
+		      XWINDOW (w->parent)->hchild = Qnil;
+		    }
+		  else
+		    {
+		      XWINDOW (w->parent)->hchild = p->window;
+		      XWINDOW (w->parent)->vchild = Qnil;
+		    }
+		}
+	    }
+	  if (!w->config_mark)
+	    {
+	      /* #### This should be equivalent to the window previously
+		 having been dead.  If we're brave, we'll put in an
+		 assertion to this effect. */
+	      MARK_FRAME_WINDOWS_STRUCTURE_CHANGED (f);
+	    }
+	  else /* if (!EQ (w->buffer, p->buffer)) */
+	    {
+	      /* With the new redisplay we let it know that a change has
+		 been made and it will take care of the rest.  If we don't
+		 tell it something has possibly changed it could lead to
+		 incorrect display. */
+	      MARK_WINDOWS_CHANGED (w);
+	    }
+
+	  WINDOW_LEFT (w) = WINDOW_LEFT (p);
+	  WINDOW_TOP (w) = WINDOW_TOP (p);
+	  WINDOW_WIDTH (w) = WINDOW_WIDTH (p);
+	  WINDOW_HEIGHT (w) = WINDOW_HEIGHT (p);
+	  w->hscroll = p->hscroll;
+	  w->modeline_hscroll = p->modeline_hscroll;
+	  w->line_cache_last_updated = Qzero;
+	  SET_LAST_MODIFIED (w, 1);
+	  SET_LAST_FACECHANGE (w);
+	  w->config_mark = 0;
+
+#define WINDOW_SLOT(slot, compare) w->slot = p->slot
+#include "winslots.h"
+
+	  /* Reinstall the saved buffer and pointers into it.  */
+	  if (NILP (p->buffer))
+	    w->buffer = p->buffer;
+	  else
+	    {
+	      if (BUFFER_LIVE_P (XBUFFER (p->buffer)))
+		/* If saved buffer is alive, install it.  */
+		{
+		  w->buffer = p->buffer;
+		  w->start_at_line_beg = p->start_at_line_beg;
+		  set_marker_restricted (w->start[CURRENT_DISP],
+					 Fmarker_position (p->start),
+					 w->buffer);
+		  set_marker_restricted (w->pointm[CURRENT_DISP],
+					 Fmarker_position (p->pointm),
+					 w->buffer);
+		  set_marker_restricted (w->sb_point,
+					 Fmarker_position (p->sb_point),
+					 w->buffer);
+		  Fset_marker (XBUFFER (w->buffer)->mark,
+			       Fmarker_position (p->mark), w->buffer);
+
+		  /* As documented in Fcurrent_window_configuration, don't
+		     save the location of point in the buffer which was current
+		     when the window configuration was recorded.  */
+		  if (!EQ (p->buffer, new_current_buffer) &&
+		      XBUFFER (p->buffer) == current_buffer)
+		    Fgoto_char (w->pointm[CURRENT_DISP], Qnil);
+		}
+	      else if (NILP (w->buffer) ||
+		       !BUFFER_LIVE_P (XBUFFER (w->buffer)))
+		/* Else if window's old buffer is dead too, get a live one.  */
+		{
+		  /* #### The following line makes me nervous... */
+		  /* w->buffer = Fcdr (Fcar (XFRAME (w->frame)->buffer_alist));*/
+		  w->buffer = Fget_buffer_create (QSscratch);
+		  /* w->buffer = Fother_buffer (Qnil, w->frame, Qnil); */
+		  /* This will set the markers to beginning of visible
+                     range.  */
+		  set_marker_restricted (w->start[CURRENT_DISP], Qzero, w->buffer);
+		  set_marker_restricted (w->pointm[CURRENT_DISP], Qzero,
+					 w->buffer);
+		  set_marker_restricted (w->sb_point, Qzero, w->buffer);
+		  w->start_at_line_beg = 1;
+		}
+	      else
+		/* Keeping window's old buffer; make sure the markers
+                   are real.  */
+		{
+		  /* Set window markers at start of visible range.  */
+		  if (XMARKER (w->start[CURRENT_DISP])->buffer == 0)
+		    set_marker_restricted (w->start[CURRENT_DISP], Qzero,
+					   w->buffer);
+		  if (XMARKER (w->sb_point)->buffer == 0)
+		    set_marker_restricted (w->sb_point, Qzero, w->buffer);
+		  if (XMARKER (w->pointm[CURRENT_DISP])->buffer == 0)
+		    set_marker_restricted (w->pointm[CURRENT_DISP],
+					   make_int
+					   (BUF_PT (XBUFFER (w->buffer))),
+					   w->buffer);
+		  w->start_at_line_beg = 1;
+		}
+	    }
+	}
+
+      FRAME_ROOT_WINDOW (f) = config->root_window;
+      /* Note that FSFmacs unilaterally calls Fselect_window() here, and
+	 then calls do_switch_frame() below to select the frame that was
+	 recorded in the window config as being selected.
+
+	 Instead, we don't ever change the selected frame, and either
+	 call Fselect_window() below if the window config's frame is
+	 currently selected, or just set the selected window of the
+	 window config's frame. */
+
+#if 0
+      /* Set the frame height to the value it had before this function.  */
+      if (previous_frame_height != FRAME_HEIGHT (f)
+	  || previous_frame_width != FRAME_WIDTH (f))
+	change_frame_size (f, previous_frame_height, previous_frame_width, 0);
+#endif
+      /* We just reset the size and position of the minibuffer, to its old
+	 value, which needn't be valid. So we do some magic to see which value
+	 to actually take. Then we set it.
+
+	 The magic:
+	 We take the old value if is in the same units but differs from the
+	 current value.
+
+         #### Now we get more cases correct then ever before, but
+	 are we treating all? For instance what if the frames minibuf window
+	 is no longer the same one? 
+      */
+      target_minibuf_height = previous_minibuf_height;
+      if (converted_minibuf_height &&
+	  (converted_minibuf_height * config->minibuf_height) > 0 &&
+	  (converted_minibuf_height !=  config->minibuf_height))
+	{
+	  target_minibuf_height = config->minibuf_height < 0 ?
+	    - (config->minibuf_height * real_font_height) :
+	    config->minibuf_height;
+	  target_minibuf_height =
+	    max(target_minibuf_height,real_font_height);
+	}
+      if (previous_minibuf_height)
+	{
+	  XWINDOW (FRAME_MINIBUF_WINDOW (f))->pixel_top
+	    = previous_minibuf_top -
+	          (target_minibuf_height - previous_minibuf_height);
+	  set_window_pixheight (FRAME_MINIBUF_WINDOW (f),
+				target_minibuf_height, 0);
+	  set_window_pixwidth  (FRAME_MINIBUF_WINDOW (f),
+			    previous_minibuf_width, 0);
+	}
+	
+      /* This is a better way to deal with frame resizing, etc.
+	 What we _actually_ want is for the old (just restored)
+	 root window to fit
+	 into the place of the new one. So we just do that. Simple! */
+      XWINDOW (FRAME_ROOT_WINDOW (f))->pixel_top = previous_pixel_top;
+      /* Note that this function also updates the subwindow
+	 "pixel_top"s */
+      set_window_pixheight (FRAME_ROOT_WINDOW (f),
+	  previous_pixel_height -
+		  (target_minibuf_height - previous_minibuf_height), 0);
+      XWINDOW (FRAME_ROOT_WINDOW (f))->pixel_left = previous_pixel_left;
+      /* Note that this function also updates the subwindow
+	 "pixel_left"s */
+      set_window_pixwidth (FRAME_ROOT_WINDOW (f), previous_pixel_width, 0);
+      
+      /* If restoring in the current frame make the window current,
+	 otherwise just update the frame selected_window slot to be
+	 the restored current_window. */
+      if (f == selected_frame ())
+	{
+	  /* When using `pop-window-configuration', often the minibuffer
+	     ends up as the selected window even though it's not active ...
+	     I really don't know the cause of this, but it should never
+	     happen.  This kludge should fix it.
+
+	     #### Find out why this is really going wrong. */
+	  if (!minibuf_level &&
+	      MINI_WINDOW_P (XWINDOW (config->current_window)))
+	    Fselect_window (Fnext_window (config->current_window,
+					  Qnil, Qnil, Qnil),
+                            Qnil);
+	  else
+	    Fselect_window (config->current_window, Qnil);
+	  if (!NILP (new_current_buffer))
+	    Fset_buffer (new_current_buffer);
+	  else
+	    Fset_buffer (XWINDOW (Fselected_window (Qnil))->buffer);
+	}
+      else
+	set_frame_selected_window (f, config->current_window);
+    }
+  else
+    old_window_config = Qnil; /* Warning suppression */
+
+  /* Restore the minimum heights recorded in the configuration.  */
+  window_min_height = config->min_height;
+  window_min_width = config->min_width;
+
+#if 0 /* FSFmacs */
+  /* see above comment */
+  /* Fselect_window will have made f the selected frame, so we
+     reselect the proper frame here.  Fhandle_switch_frame will change the
+     selected window too, but that doesn't make the call to
+     Fselect_window above totally superfluous; it still sets f's
+     selected window.  */
+  if (FRAME_LIVE_P (XFRAME (config->selected_frame)))
+    do_switch_frame (config->selected_frame, Qnil, 0);
+#endif
+
+  Vminibuffer_scroll_window = config->minibuffer_scroll_window;
+
+  if (FRAME_LIVE_P (f))
+    {
+      /* Do this before calling recompute_all_cached_specifiers_in_window()
+	 so that things like redisplay_redraw_cursor() won't abort due
+	 to no window mirror present. */
+      f->mirror_dirty = 1;
+
+      config = XWINDOW_CONFIGURATION (old_window_config);
+      for (k = 0; k < config->saved_windows_count; k++)
+	{
+	  p = SAVED_WINDOW_N (config, k);
+	  w = XWINDOW (p->window);
+	  /* Remember, we set w->config_mark on all currently visible
+	     windows, and reset it on all newly visible windows.
+	     Any windows still marked need to be deleted. */
+	  if (w->config_mark)
+	    {
+	      mark_window_as_deleted (w);
+	      w->config_mark = 0;
+	    }
+	  else
+	    {
+	      /* We just potentially changed the window's buffer and
+		 potentially turned a dead window into a live one,
+		 so we need to recompute the cached specifier values. */
+	      recompute_all_cached_specifiers_in_window (w);
+	    }
+	}
+    }
+
+  /* Now restore things, when everything else if OK. */
+
+  unbind_to (specpdl_count, Qnil);
+
+  UNGCPRO;
+
+  return Qnil;
+}
+
+/* Mark all subwindows of a window as deleted.  The argument
+   W is actually the subwindow tree of the window in question. */
+
+void
+delete_all_subwindows (struct window *w)
+{
+  if (!NILP (w->next))   delete_all_subwindows (XWINDOW (w->next));
+  if (!NILP (w->vchild)) delete_all_subwindows (XWINDOW (w->vchild));
+  if (!NILP (w->hchild)) delete_all_subwindows (XWINDOW (w->hchild));
+
+  mark_window_as_deleted (w);
+}
+
+
+static int
+count_windows (struct window *window)
+{
+  return 1 +
+    (!NILP (window->next)   ? count_windows (XWINDOW (window->next))   : 0) +
+    (!NILP (window->vchild) ? count_windows (XWINDOW (window->vchild)) : 0) +
+    (!NILP (window->hchild) ? count_windows (XWINDOW (window->hchild)) : 0);
+}
+
+static int
+saved_window_index (Lisp_Object window, struct window_config *config, int lim)
+{
+  int j;
+  for (j = 0; j < lim; j++)
+    {
+      if (EQ (SAVED_WINDOW_N (config, j)->window, window))
+	return j;
+    }
+  abort ();
+  return 0;	/* suppress compiler warning */
+}
+
+static int
+save_window_save (Lisp_Object window, struct window_config *config, int i)
+{
+  struct window *w;
+
+  for (; !NILP (window); window = w->next)
+    {
+      struct saved_window *p = SAVED_WINDOW_N (config, i);
+
+      w = XWINDOW (window);
+      i++;
+      p->window = window;
+      p->buffer = w->buffer;
+      WINDOW_LEFT (p) = WINDOW_LEFT (w);
+      WINDOW_TOP (p) = WINDOW_TOP (w);
+      WINDOW_WIDTH (p) = WINDOW_WIDTH (w);
+      WINDOW_HEIGHT (p) = WINDOW_HEIGHT (w);
+      p->hscroll = w->hscroll;
+      p->modeline_hscroll = w->modeline_hscroll;
+
+#define WINDOW_SLOT(slot, compare) p->slot = w->slot
+#include "winslots.h"
+
+      if (!NILP (w->buffer))
+	{
+	  /* Save w's value of point in the window configuration.
+	     If w is the selected window, then get the value of point
+	     from the buffer; pointm is garbage in the selected window.  */
+	  if (EQ (window, Fselected_window (Qnil)))
+	    {
+	      p->pointm = noseeum_make_marker ();
+	      Fset_marker (p->pointm,
+			   make_int (BUF_PT (XBUFFER (w->buffer))),
+			   w->buffer);
+	    }
+	  else
+	    p->pointm = noseeum_copy_marker (w->pointm[CURRENT_DISP], Qnil);
+
+	  p->start = noseeum_copy_marker (w->start[CURRENT_DISP], Qnil);
+	  p->sb_point = noseeum_copy_marker (w->sb_point, Qnil);
+	  p->start_at_line_beg = w->start_at_line_beg;
+
+	  p->mark = noseeum_copy_marker (XBUFFER (w->buffer)->mark, Qnil);
+	}
+      else
+	{
+	  p->pointm = Qnil;
+	  p->start = Qnil;
+	  p->sb_point = Qnil;
+	  p->mark = Qnil;
+	  p->start_at_line_beg = 0;
+	}
+
+      if (NILP (w->parent))
+	p->parent_index = -1;
+      else
+        p->parent_index = saved_window_index (w->parent, config, i);
+      if (NILP (w->prev))
+	p->prev_index = -1;
+      else
+        p->prev_index = saved_window_index (w->prev, config, i);
+      if (!NILP (w->vchild))
+	i = save_window_save (w->vchild, config, i);
+      if (!NILP (w->hchild))
+	i = save_window_save (w->hchild, config, i);
+    }
+
+  return i;
+}
+
+#if 0 /* FSFmacs */
+/* Added to doc string:
+
+This also records the currently selected frame, and FRAME's focus
+redirection (see `redirect-frame-focus').
+
+*/
+#endif
+
+DEFUN ("current-window-configuration", Fcurrent_window_configuration, 0, 1, 0, /*
+Return an object representing the current window configuration of FRAME.
+If FRAME is nil or omitted, use the selected frame.
+This describes the number of windows, their sizes and current buffers,
+and for each displayed buffer, where display starts, and the positions of
+point and mark.  An exception is made for point in the current buffer:
+its value is -not- saved.
+*/
+       (frame))
+{
+  Lisp_Object result;
+  struct frame *f = decode_frame (frame);
+  struct window_config *config;
+  int n_windows = count_windows (XWINDOW (FRAME_ROOT_WINDOW (f)));
+  int minibuf_height;
+  int real_font_height;
+
+  if (n_windows <= countof (Vwindow_configuration_free_list))
+    config = XWINDOW_CONFIGURATION (allocate_managed_lcrecord
+				    (Vwindow_configuration_free_list
+				     [n_windows - 1]));
+  else
+    /* More than ten windows; just allocate directly */
+    config = (struct window_config *)
+      alloc_lcrecord (sizeof_window_config_for_n_windows (n_windows),
+		      &lrecord_window_configuration);
+  XSETWINDOW_CONFIGURATION (result, config);
+  /*
+  config->frame_width = FRAME_WIDTH (f);
+  config->frame_height = FRAME_HEIGHT (f); */
+  config->current_window = FRAME_SELECTED_WINDOW (f);
+  XSETBUFFER (config->current_buffer, current_buffer);
+  config->minibuffer_scroll_window = Vminibuffer_scroll_window;
+  config->root_window = FRAME_ROOT_WINDOW (f);
+  config->min_height = window_min_height;
+  config->min_width = window_min_width;
+  config->saved_windows_count = n_windows;
+  save_window_save (FRAME_ROOT_WINDOW (f), config, 0);
+
+  /* save the minibuffer height using the heuristics from
+     change_frame_size_1 */
+  
+  XSETFRAME (frame, f); /* frame could have been nil ! */
+  default_face_height_and_width (frame, &real_font_height, 0);
+  assert(real_font_height > 0);
+  
+  if (FRAME_HAS_MINIBUF_P (f) && ! FRAME_MINIBUF_ONLY_P (f))
+    minibuf_height = XWINDOW(FRAME_MINIBUF_WINDOW(f))->pixel_height;
+  else
+    minibuf_height = 0;
+  config->minibuf_height = (minibuf_height % real_font_height) == 0 ?
+    - (minibuf_height / real_font_height ) :    /* lines */
+    minibuf_height;   /* pixels */
+
+  return result;
+}
+
+Lisp_Object
+save_window_excursion_unwind (Lisp_Object window_config)
+{
+  Lisp_Object val = Fset_window_configuration (window_config);
+  free_window_configuration (window_config);
+  return val;
+}
+
+DEFUN ("save-window-excursion", Fsave_window_excursion, 0, UNEVALLED, 0, /*
+Execute body, preserving window sizes and contents.
+Restores which buffer appears in which window, where display starts,
+as well as the current buffer.
+Does not restore the value of point in current buffer.
+*/
+       (args))
+{
+  /* This function can GC */
+  Lisp_Object val;
+  int speccount = specpdl_depth ();
+
+  record_unwind_protect (save_window_excursion_unwind,
+			 Fcurrent_window_configuration (Qnil));
+  val = Fprogn (args);
+  return unbind_to (speccount, val);
+}
+
+DEFUN ("current-pixel-column", Fcurrent_pixel_column, 0, 2, 0, /*
+Return the horizontal pixel position of POS in window.
+Beginning of line is column 0. This is calculated using the redisplay
+display tables.  If WINDOW is nil, the current window is assumed.
+If POS is nil, point is assumed. Note that POS must be visible for
+a non-nil result to be returned.
+*/
+       (window, pos))
+{
+  struct window* w = decode_window (window);
+  display_line_dynarr *dla = window_display_lines (w, CURRENT_DISP);
+
+  struct display_line *dl = 0;
+  struct display_block *db = 0;
+  struct rune* rb = 0;
+  int y = w->last_point_y[CURRENT_DISP];
+  int x = w->last_point_x[CURRENT_DISP];
+
+  if (MINI_WINDOW_P (w))
+    return Qnil;
+
+  if (y<0 || x<0 || y >= Dynarr_length (dla) || !NILP (pos))
+    {
+      int first_line, i;
+      Bufpos point;
+
+      if (NILP (pos))
+	pos = Fwindow_point (window);
+      
+      CHECK_INT (pos);
+      point = XINT (pos);
+
+      if (Dynarr_length (dla) && Dynarr_atp (dla, 0)->modeline)
+	first_line = 1;
+      else
+	first_line = 0;
+
+      for (i = first_line; i < Dynarr_length (dla); i++)
+	{
+	  dl = Dynarr_atp (dla, i);
+	  /* find the vertical location first */
+	  if (point >= dl->bufpos && point <= dl->end_bufpos)
+	    {
+	      db = get_display_block_from_line (dl, TEXT);
+	      for (i = 0; i < Dynarr_length (db->runes); i++)
+		{
+		  rb = Dynarr_atp (db->runes, i);
+		  if (point <= rb->bufpos)
+		    goto found_bufpos;
+		}
+	      return Qnil;
+	    }
+	}
+      return Qnil;
+    found_bufpos:
+      ;
+    }
+  else
+    {
+      /* optimised case */
+      dl = Dynarr_atp (dla, y);
+      db = get_display_block_from_line (dl, TEXT);
+
+      if (x >= Dynarr_length (db->runes))
+	return Qnil;
+
+      rb = Dynarr_atp (db->runes, x);
+    }
+
+  return make_int (rb->xpos - WINDOW_LEFT (w));
+}
+
+
+#ifdef DEBUG_XEMACS
+/* This is short and simple in elisp, but... it was written to debug
+   problems purely on the C side.  That is where we need to call it so
+   here it is. */
+static void
+debug_print_window (Lisp_Object window, int level)
+{
+  int i;
+  Lisp_Object child = Fwindow_first_vchild (window);
+
+  if (NILP (child))
+    child = Fwindow_first_hchild (window);
+
+  for (i = level; i > 0; i--)
+    putc ('\t', stderr);
+
+  fputs ("#<window", stderr);
+  {
+    Lisp_Object buffer = XWINDOW (window)->buffer;
+    if (!NILP (buffer) && BUFFERP (buffer))
+      fprintf (stderr, " on %s", XSTRING_DATA (XBUFFER (buffer)->name));
+  }
+  fprintf (stderr, " 0x%x>", XWINDOW (window)->header.uid);
+
+  while (!NILP (child))
+    {
+      debug_print_window (child, level + 1);
+      child = Fwindow_next_child (child);
+    }
+}
+
+void debug_print_windows (struct frame *f);
+void
+debug_print_windows (struct frame *f)
+{
+  debug_print_window (f->root_window, 0);
+  putc ('\n', stderr);
+}
+#endif /* DEBUG_XEMACS */
+
+
+/************************************************************************/
+/*                            initialization                            */
+/************************************************************************/
+
+void
+syms_of_window (void)
+{
+  defsymbol (&Qwindowp, "windowp");
+  defsymbol (&Qwindow_live_p, "window-live-p");
+  defsymbol (&Qwindow_configurationp, "window-configuration-p");
+  defsymbol (&Qtemp_buffer_show_hook, "temp-buffer-show-hook");
+  defsymbol (&Qdisplay_buffer, "display-buffer");
+
+#ifdef MEMORY_USAGE_STATS
+  defsymbol (&Qface_cache, "face-cache");
+  defsymbol (&Qglyph_cache, "glyph-cache");
+  defsymbol (&Qline_start_cache, "line-start-cache");
+#ifdef HAVE_SCROLLBARS
+  defsymbol (&Qscrollbar_instances, "scrollbar-instances");
+#endif
+  defsymbol (&Qother_redisplay, "other-redisplay");
+  /* Qother in general.c */
+#endif
+
+  DEFSUBR (Fselected_window);
+  DEFSUBR (Flast_nonminibuf_window);
+  DEFSUBR (Fminibuffer_window);
+  DEFSUBR (Fwindow_minibuffer_p);
+  DEFSUBR (Fwindowp);
+  DEFSUBR (Fwindow_live_p);
+  DEFSUBR (Fwindow_first_hchild);
+  DEFSUBR (Fwindow_first_vchild);
+  DEFSUBR (Fwindow_next_child);
+  DEFSUBR (Fwindow_previous_child);
+  DEFSUBR (Fwindow_parent);
+  DEFSUBR (Fwindow_lowest_p);
+  DEFSUBR (Fwindow_truncated_p);
+  DEFSUBR (Fwindow_highest_p);
+  DEFSUBR (Fwindow_leftmost_p);
+  DEFSUBR (Fwindow_rightmost_p);
+  DEFSUBR (Fpos_visible_in_window_p);
+  DEFSUBR (Fwindow_buffer);
+  DEFSUBR (Fwindow_frame);
+  DEFSUBR (Fwindow_height);
+  DEFSUBR (Fwindow_displayed_height);
+  DEFSUBR (Fwindow_width);
+  DEFSUBR (Fwindow_pixel_height);
+  DEFSUBR (Fwindow_pixel_width);
+  DEFSUBR (Fwindow_text_area_pixel_height);
+  DEFSUBR (Fwindow_displayed_text_pixel_height);
+  DEFSUBR (Fwindow_text_area_pixel_width);
+  DEFSUBR (Fwindow_hscroll);
+#ifdef MODELINE_IS_SCROLLABLE
+  DEFSUBR (Fmodeline_hscroll);
+  DEFSUBR (Fset_modeline_hscroll);
+#endif /* MODELINE_IS_SCROLLABLE */
+#if 0 /* bogus FSF crock */
+  DEFSUBR (Fwindow_redisplay_end_trigger);
+  DEFSUBR (Fset_window_redisplay_end_trigger);
+#endif
+  DEFSUBR (Fset_window_hscroll);
+  DEFSUBR (Fwindow_pixel_edges);
+  DEFSUBR (Fwindow_text_area_pixel_edges);
+  DEFSUBR (Fwindow_point);
+  DEFSUBR (Fwindow_start);
+  DEFSUBR (Fwindow_end);
+  DEFSUBR (Fset_window_point);
+  DEFSUBR (Fset_window_start);
+  DEFSUBR (Fwindow_dedicated_p);
+  DEFSUBR (Fset_window_dedicated_p);
+  DEFSUBR (Fnext_window);
+  DEFSUBR (Fprevious_window);
+  DEFSUBR (Fnext_vertical_window);
+  DEFSUBR (Fother_window);
+  DEFSUBR (Fget_lru_window);
+  DEFSUBR (Fget_largest_window);
+  DEFSUBR (Fget_buffer_window);
+  DEFSUBR (Fwindow_left_margin_pixel_width);
+  DEFSUBR (Fwindow_right_margin_pixel_width);
+  DEFSUBR (Fdelete_other_windows);
+  DEFSUBR (Fdelete_windows_on);
+  DEFSUBR (Freplace_buffer_in_windows);
+  DEFSUBR (Fdelete_window);
+  DEFSUBR (Fset_window_buffer);
+  DEFSUBR (Fselect_window);
+  DEFSUBR (Fsplit_window);
+  DEFSUBR (Fenlarge_window);
+  DEFSUBR (Fenlarge_window_pixels);
+  DEFSUBR (Fshrink_window);
+  DEFSUBR (Fshrink_window_pixels);
+  DEFSUBR (Fscroll_up);
+  DEFSUBR (Fscroll_down);
+  DEFSUBR (Fscroll_left);
+  DEFSUBR (Fscroll_right);
+  DEFSUBR (Fother_window_for_scrolling);
+  DEFSUBR (Fscroll_other_window);
+  DEFSUBR (Fcenter_to_window_line);
+  DEFSUBR (Fmove_to_window_line);
+#ifdef MEMORY_USAGE_STATS
+  DEFSUBR (Fwindow_memory_usage);
+#endif
+  DEFSUBR (Fwindow_configuration_p);
+  DEFSUBR (Fset_window_configuration);
+  DEFSUBR (Fcurrent_window_configuration);
+  DEFSUBR (Fsave_window_excursion);
+  DEFSUBR (Fcurrent_pixel_column);
+}
+
+void
+reinit_vars_of_window (void)
+{
+  int i;
+  /* Make sure all windows get marked */
+  minibuf_window = Qnil;
+  staticpro_nodump (&minibuf_window);
+
+  for (i = 0; i < countof (Vwindow_configuration_free_list); i++)
+    {
+      Vwindow_configuration_free_list[i] =
+	make_lcrecord_list (sizeof_window_config_for_n_windows (i + 1),
+			    &lrecord_window_configuration);
+      staticpro_nodump (&Vwindow_configuration_free_list[i]);
+    }
+}
+
+void
+vars_of_window (void)
+{
+  reinit_vars_of_window ();
+
+  DEFVAR_BOOL ("scroll-on-clipped-lines", &scroll_on_clipped_lines /*
+*Non-nil means to scroll if point lands on a line which is clipped.
+*/ );
+  scroll_on_clipped_lines = 1;
+
+  DEFVAR_LISP ("temp-buffer-show-hook", &Vtemp_buffer_show_hook /*
+See `temp-buffer-show-function'.
+*/ );
+  Vtemp_buffer_show_hook = Qnil;
+
+  DEFVAR_LISP ("temp-buffer-show-function", &Vtemp_buffer_show_function /*
+Non-nil means call as function to display a help buffer.
+The function is called with one argument, the buffer to be displayed.
+Used by `with-output-to-temp-buffer'.
+If this function is used, then it must do the entire job of showing
+the buffer; `temp-buffer-show-hook' is not run unless this function runs it.
+*/ );
+  Vtemp_buffer_show_function = Qnil;
+
+  DEFVAR_LISP ("minibuffer-scroll-window", &Vminibuffer_scroll_window /*
+Non-nil means it is the window that \\<minibuffer-local-map>\\[scroll-other-window] in minibuffer should scroll.
+*/ );
+  Vminibuffer_scroll_window = Qnil;
+
+  DEFVAR_LISP ("other-window-scroll-buffer", &Vother_window_scroll_buffer /*
+If non-nil, this is a buffer and \\[scroll-other-window] should scroll its window.
+*/ );
+  Vother_window_scroll_buffer = Qnil;
+
+  DEFVAR_LISP ("window-pixel-scroll-increment", &Vwindow_pixel_scroll_increment /*
+*Number of pixels to scroll by per requested line.
+If nil then normal line scrolling occurs regardless of line height.
+If t then scrolling is done in increments equal to the height of the default face.
+*/ );
+  Vwindow_pixel_scroll_increment = Qt;
+
+  DEFVAR_INT ("next-screen-context-lines", &next_screen_context_lines /*
+*Number of lines of continuity when scrolling by screenfuls.
+*/ );
+  next_screen_context_lines = 2;
+
+  DEFVAR_INT ("window-min-height", &window_min_height /*
+*Delete any window less than this tall (including its modeline).
+*/ );
+  window_min_height = 4;
+
+  DEFVAR_INT ("window-min-width", &window_min_width /*
+*Delete any window less than this wide.
+*/ );
+  window_min_width = 10;
+}
+
+void
+specifier_vars_of_window (void)
+{
+  DEFVAR_SPECIFIER ("modeline-shadow-thickness", &Vmodeline_shadow_thickness /*
+*How thick to draw 3D shadows around modelines.
+If this is set to 0, modelines will be the traditional 2D.  Sizes above
+10 will be accepted but the maximum thickness that will be drawn is 10.
+This is a specifier; use `set-specifier' to change it.
+*/ );
+  Vmodeline_shadow_thickness = Fmake_specifier (Qinteger);
+  /* The initial value for modeline-shadow-thickness is 2, but if the
+     user removes all specifications we provide a fallback value of 0,
+     which is probably what was expected. */
+  set_specifier_fallback (Vmodeline_shadow_thickness,
+			  list1 (Fcons (Qnil, Qzero)));
+  Fadd_spec_to_specifier (Vmodeline_shadow_thickness, make_int (2),
+			  Qnil, Qnil, Qnil);
+  set_specifier_caching (Vmodeline_shadow_thickness,
+			 slot_offset (struct window,
+				      modeline_shadow_thickness),
+			 modeline_shadow_thickness_changed,
+			 0, 0);
+
+  DEFVAR_SPECIFIER ("has-modeline-p", &Vhas_modeline_p /*
+*Whether the modeline should be displayed.
+This is a specifier; use `set-specifier' to change it.
+*/ );
+  Vhas_modeline_p = Fmake_specifier (Qboolean);
+  set_specifier_fallback (Vhas_modeline_p,
+			  list1 (Fcons (Qnil, Qt)));
+  set_specifier_caching (Vhas_modeline_p,
+			 slot_offset (struct window,
+				      has_modeline_p),
+			 /* #### It's strange that we need a special
+			    flag to indicate that the shadow-thickness
+			    has changed, but not one to indicate that
+			    the modeline has been turned off or on. */
+			 some_window_value_changed,
+			 0, 0);
+
+  DEFVAR_SPECIFIER ("vertical-divider-always-visible-p",
+		    &Vvertical_divider_always_visible_p /*
+*Should XEmacs always display vertical dividers between windows.
+
+When this is non-nil, vertical dividers are always shown, and are
+draggable.  When it is nil, vertical dividers are shown only when
+there are no scrollbars in between windows, and are not draggable.
+
+This is a specifier; use `set-specifier' to change it.
+*/ );
+  Vvertical_divider_always_visible_p = Fmake_specifier (Qboolean);
+  set_specifier_fallback (Vvertical_divider_always_visible_p,
+			  list1 (Fcons (Qnil, Qt)));
+  set_specifier_caching (Vvertical_divider_always_visible_p,
+			 slot_offset (struct window,
+				      vertical_divider_always_visible_p),
+			 vertical_divider_changed_in_window,
+ 			 0, 0);
+
+  DEFVAR_SPECIFIER ("vertical-divider-shadow-thickness", &Vvertical_divider_shadow_thickness /*
+*How thick to draw 3D shadows around vertical dividers.
+This is a specifier; use `set-specifier' to change it.
+*/ );
+  Vvertical_divider_shadow_thickness = Fmake_specifier (Qinteger);
+  set_specifier_fallback (Vvertical_divider_shadow_thickness,
+			  list1 (Fcons (Qnil, Qzero)));
+  Fadd_spec_to_specifier (Vvertical_divider_shadow_thickness, make_int (2),
+			  Qnil, Qnil, Qnil);
+  set_specifier_caching (Vvertical_divider_shadow_thickness,
+			 slot_offset (struct window,
+				      vertical_divider_shadow_thickness),
+			 vertical_divider_changed_in_window,
+ 			 0, 0);
+  DEFVAR_SPECIFIER ("vertical-divider-line-width", &Vvertical_divider_line_width /*
+*The width of the vertical dividers, not including shadows.
+
+For TTY windows, divider line is always one character wide.  When
+instance of this specifier is zero in a TTY window, no divider is
+drawn at all between windows.  When non-zero, a one character wide
+divider is displayed.
+
+This is a specifier; use `set-specifier' to change it.
+*/ );
+
+  Vvertical_divider_line_width = Fmake_specifier (Qnatnum);
+  {
+    Lisp_Object fb = Qnil;
+#ifdef HAVE_TTY
+    fb = Fcons (Fcons (list1 (Qtty), make_int (1)), fb);
+#endif
+#ifdef HAVE_X_WINDOWS
+    fb = Fcons (Fcons (list1 (Qx), make_int (3)), fb);
+#endif
+#ifdef HAVE_MS_WINDOWS
+    /* #### This should be made magic and made to obey system settings */
+    fb = Fcons (Fcons (list1 (Qmswindows), make_int (3)), fb);
+#endif
+    set_specifier_fallback (Vvertical_divider_line_width, fb);
+  }
+  set_specifier_caching (Vvertical_divider_line_width,
+                         slot_offset (struct window,
+				      vertical_divider_line_width),
+			 vertical_divider_changed_in_window,
+                         0, 0);
+
+  DEFVAR_SPECIFIER ("vertical-divider-spacing", &Vvertical_divider_spacing /*
+*How much space to leave around the vertical dividers.
+
+In TTY windows, spacing is always zero, and the value of this
+specifier is ignored.
+
+This is a specifier; use `set-specifier' to change it.
+*/ );
+  Vvertical_divider_spacing = Fmake_specifier (Qnatnum);
+  {
+    Lisp_Object fb = Qnil;
+#ifdef HAVE_TTY
+    fb = Fcons (Fcons (list1 (Qtty), Qzero), fb);
+#endif
+#ifdef HAVE_X_WINDOWS
+    /* #### 3D dividers look great on MS Windows with spacing = 0.
+       Should not the same value be the fallback under X? - kkm */
+    fb = Fcons (Fcons (list1 (Qx), make_int (2)), fb);
+#endif
+#ifdef HAVE_MS_WINDOWS
+    fb = Fcons (Fcons (list1 (Qmswindows), Qzero), fb);
+#endif
+    set_specifier_fallback (Vvertical_divider_spacing, fb);
+  }
+  set_specifier_caching (Vvertical_divider_spacing,
+			 slot_offset (struct window,
+				      vertical_divider_spacing),
+			 vertical_divider_changed_in_window,
+			 0, 0);
+}