text: /* vi:set ts=8 sts=4 sw=4 noet:
   *
   * VIM - Vi IMproved	by Bram Moolenaar
   *
   * Do ":help uganda"  in Vim to read a list of people who contributed.
   * Do ":help credits" in Vim to see a list of people who contributed.
   * See README.txt for an overview of the Vim source code.
   */
  
  #include "vim.h"
  
  static void cmd_with_count(char *cmd, char_u *bufp, size_t bufsize, long Prenum);
  static void win_init(win_T *newp, win_T *oldp, int flags);
  static void win_init_some(win_T *newp, win_T *oldp);
  static void frame_comp_pos(frame_T *topfrp, int *row, int *col);
  static void frame_setheight(frame_T *curfrp, int height);
  static void frame_setwidth(frame_T *curfrp, int width);
  static void win_exchange(long);
  static void win_rotate(int, int);
  static void win_totop(int size, int flags);
  static void win_equal_rec(win_T *next_curwin, int current, frame_T *topfr, int dir, int col, int row, int width, int height);
  static void trigger_winclosed(win_T *win);
  static win_T *win_free_mem(win_T *win, int *dirp, tabpage_T *tp);
  static frame_T *win_altframe(win_T *win, tabpage_T *tp);
  static tabpage_T *alt_tabpage(void);
  static win_T *frame2win(frame_T *frp);
  static int frame_has_win(frame_T *frp, win_T *wp);
  static void frame_new_height(frame_T *topfrp, int height, int topfirst, int wfh);
  static int frame_fixed_height(frame_T *frp);
  static int frame_fixed_width(frame_T *frp);
  static void frame_add_statusline(frame_T *frp);
  static void frame_new_width(frame_T *topfrp, int width, int leftfirst, int wfw);
  static void frame_add_vsep(frame_T *frp);
  static int frame_minwidth(frame_T *topfrp, win_T *next_curwin);
  static void frame_fix_width(win_T *wp);
  static int win_alloc_firstwin(win_T *oldwin);
  static void new_frame(win_T *wp);
  static tabpage_T *alloc_tabpage(void);
  static int leave_tabpage(buf_T *new_curbuf, int trigger_leave_autocmds);
  static void enter_tabpage(tabpage_T *tp, buf_T *old_curbuf, int trigger_enter_autocmds, int trigger_leave_autocmds);
  static void frame_fix_height(win_T *wp);
  static int frame_minheight(frame_T *topfrp, win_T *next_curwin);
  static int may_open_tabpage(void);
  static int win_enter_ext(win_T *wp, int flags);
  static void win_free(win_T *wp, tabpage_T *tp);
  static void win_append(win_T *after, win_T *wp);
  static void frame_append(frame_T *after, frame_T *frp);
  static void frame_insert(frame_T *before, frame_T *frp);
  static void frame_remove(frame_T *frp);
  static void win_goto_ver(int up, long count);
  static void win_goto_hor(int left, long count);
  static void frame_add_height(frame_T *frp, int n);
  static void last_status_rec(frame_T *fr, int statusline);
  
  static void make_snapshot_rec(frame_T *fr, frame_T **frp);
  static void clear_snapshot(tabpage_T *tp, int idx);
  static void clear_snapshot_rec(frame_T *fr);
  static int check_snapshot_rec(frame_T *sn, frame_T *fr);
  static win_T *restore_snapshot_rec(frame_T *sn, frame_T *fr);
  
  static int frame_check_height(frame_T *topfrp, int height);
  static int frame_check_width(frame_T *topfrp, int width);
  
  static win_T *win_alloc(win_T *after, int hidden);
  
  #define NOWIN		((win_T *)-1)	// non-existing window
  
  #define ROWS_AVAIL (Rows - p_ch - tabline_height())
  
  // flags for win_enter_ext()
  #define WEE_UNDO_SYNC			0x01
  #define WEE_CURWIN_INVALID		0x02
  #define WEE_TRIGGER_NEW_AUTOCMDS	0x04
  #define WEE_TRIGGER_ENTER_AUTOCMDS	0x08
  #define WEE_TRIGGER_LEAVE_AUTOCMDS	0x10
  #define WEE_ALLOW_PARSE_MESSAGES	0x20
  
  static char *m_onlyone = N_("Already only one window");
  
  // When non-zero splitting a window is forbidden.  Used to avoid that nasty
  // autocommands mess up the window structure.
  static int split_disallowed = 0;
  
  // #define WIN_DEBUG
  #ifdef WIN_DEBUG
  /*
   * Call this method to log the current window layout.
   */
      static void
  log_frame_layout(frame_T *frame)
  {
      ch_log(NULL, "layout %s, wi: %d, he: %d, wwi: %d, whe: %d, id: %d",
  	    frame->fr_layout == FR_LEAF ? "LEAF"
  				  : frame->fr_layout == FR_ROW ? "ROW" : "COL",
  	    frame->fr_width,
  	    frame->fr_height,
  	    frame->fr_win == NULL ? -1 : frame->fr_win->w_width,
  	    frame->fr_win == NULL ? -1 : frame->fr_win->w_height,
  	    frame->fr_win == NULL ? -1 : frame->fr_win->w_id);
      if (frame->fr_child != NULL)
      {
  	ch_log(NULL, "children");
  	log_frame_layout(frame->fr_child);
  	if (frame->fr_next != NULL)
  	    ch_log(NULL, "END of children");
      }
      if (frame->fr_next != NULL)
  	log_frame_layout(frame->fr_next);
  }
  #endif
  
  /*
   * Return the current window, unless in the cmdline window and "prevwin" is
   * set, then return "prevwin".
   */
      win_T *
  prevwin_curwin(void)
  {
      return
  #ifdef FEAT_CMDWIN
  	// In cmdwin, the alternative buffer should be used.
  	is_in_cmdwin() && prevwin != NULL ? prevwin :
  #endif
  	curwin;
  }
  
  /*
   * All CTRL-W window commands are handled here, called from normal_cmd().
   */
      void
  do_window(
      int		nchar,
      long	Prenum,
      int		xchar)	    // extra char from ":wincmd gx" or NUL
  {
      long	Prenum1;
      win_T	*wp;
  #if defined(FEAT_SEARCHPATH) || defined(FEAT_FIND_ID)
      char_u	*ptr;
      linenr_T    lnum = -1;
  #endif
  #ifdef FEAT_FIND_ID
      int		type = FIND_DEFINE;
      int		len;
  #endif
      char_u	cbuf[40];
  
      if (ERROR_IF_ANY_POPUP_WINDOW)
  	return;
  
  #ifdef FEAT_CMDWIN
  # define CHECK_CMDWIN \
      do { \
  	if (cmdwin_type != 0) \
  	{ \
  	    emsg(_(e_invalid_in_cmdline_window)); \
  	    return; \
  	} \
      } while (0)
  #else
  # define CHECK_CMDWIN do { /**/ } while (0)
  #endif
  
      Prenum1 = Prenum == 0 ? 1 : Prenum;
  
      switch (nchar)
      {
  // split current window in two parts, horizontally
      case 'S':
      case Ctrl_S:
      case 's':
  		CHECK_CMDWIN;
  		reset_VIsual_and_resel();	// stop Visual mode
  #ifdef FEAT_QUICKFIX
  		// When splitting the quickfix window open a new buffer in it,
  		// don't replicate the quickfix buffer.
  		if (bt_quickfix(curbuf))
  		    goto newwindow;
  #endif
  #ifdef FEAT_GUI
  		need_mouse_correct = TRUE;
  #endif
  		(void)win_split((int)Prenum, 0);
  		break;
  
  // split current window in two parts, vertically
      case Ctrl_V:
      case 'v':
  		CHECK_CMDWIN;
  		reset_VIsual_and_resel();	// stop Visual mode
  #ifdef FEAT_QUICKFIX
  		// When splitting the quickfix window open a new buffer in it,
  		// don't replicate the quickfix buffer.
  		if (bt_quickfix(curbuf))
  		    goto newwindow;
  #endif
  #ifdef FEAT_GUI
  		need_mouse_correct = TRUE;
  #endif
  		(void)win_split((int)Prenum, WSP_VERT);
  		break;
  
  // split current window and edit alternate file
      case Ctrl_HAT:
      case '^':
  		CHECK_CMDWIN;
  		reset_VIsual_and_resel();	// stop Visual mode
  
  		if (buflist_findnr(Prenum == 0
  					? curwin->w_alt_fnum : Prenum) == NULL)
  		{
  		    if (Prenum == 0)
  			emsg(_(e_no_alternate_file));
  		    else
  			semsg(_(e_buffer_nr_not_found), Prenum);
  		    break;
  		}
  
  		if (!curbuf_locked() && win_split(0, 0) == OK)
  		    (void)buflist_getfile(
  			    Prenum == 0 ? curwin->w_alt_fnum : Prenum,
  			    (linenr_T)0, GETF_ALT, FALSE);
  		break;
  
  // open new window
      case Ctrl_N:
      case 'n':
  		CHECK_CMDWIN;
  		reset_VIsual_and_resel();	// stop Visual mode
  #ifdef FEAT_QUICKFIX
  newwindow:
  #endif
  		if (Prenum)
  		    // window height
  		    vim_snprintf((char *)cbuf, sizeof(cbuf) - 5, "%ld", Prenum);
  		else
  		    cbuf[0] = NUL;
  #if defined(FEAT_QUICKFIX)
  		if (nchar == 'v' || nchar == Ctrl_V)
  		    STRCAT(cbuf, "v");
  #endif
  		STRCAT(cbuf, "new");
  		do_cmdline_cmd(cbuf);
  		break;
  
  // quit current window
      case Ctrl_Q:
      case 'q':
  		reset_VIsual_and_resel();	// stop Visual mode
  		cmd_with_count("quit", cbuf, sizeof(cbuf), Prenum);
  		do_cmdline_cmd(cbuf);
  		break;
  
  // close current window
      case Ctrl_C:
      case 'c':
  		reset_VIsual_and_resel();	// stop Visual mode
  		cmd_with_count("close", cbuf, sizeof(cbuf), Prenum);
  		do_cmdline_cmd(cbuf);
  		break;
  
  #if defined(FEAT_QUICKFIX)
  // close preview window
      case Ctrl_Z:
      case 'z':
  		CHECK_CMDWIN;
  		reset_VIsual_and_resel();	// stop Visual mode
  		do_cmdline_cmd((char_u *)"pclose");
  		break;
  
  // cursor to preview window
      case 'P':
  		FOR_ALL_WINDOWS(wp)
  		    if (wp->w_p_pvw)
  			break;
  		if (wp == NULL)
  		    emsg(_(e_there_is_no_preview_window));
  		else
  		    win_goto(wp);
  		break;
  #endif
  
  // close all but current window
      case Ctrl_O:
      case 'o':
  		CHECK_CMDWIN;
  		reset_VIsual_and_resel();	// stop Visual mode
  		cmd_with_count("only", cbuf, sizeof(cbuf), Prenum);
  		do_cmdline_cmd(cbuf);
  		break;
  
  // cursor to next window with wrap around
      case Ctrl_W:
      case 'w':
  // cursor to previous window with wrap around
      case 'W':
  		CHECK_CMDWIN;
  		if (ONE_WINDOW && Prenum != 1)	// just one window
  		    beep_flush();
  		else
  		{
  		    if (Prenum)			// go to specified window
  		    {
  			for (wp = firstwin; --Prenum > 0; )
  			{
  			    if (wp->w_next == NULL)
  				break;
  			    else
  				wp = wp->w_next;
  			}
  		    }
  		    else
  		    {
  			if (nchar == 'W')	    // go to previous window
  			{
  			    wp = curwin->w_prev;
  			    if (wp == NULL)
  				wp = lastwin;	    // wrap around
  			}
  			else			    // go to next window
  			{
  			    wp = curwin->w_next;
  			    if (wp == NULL)
  				wp = firstwin;	    // wrap around
  			}
  		    }
  		    win_goto(wp);
  		}
  		break;
  
  // cursor to window below
      case 'j':
      case K_DOWN:
      case Ctrl_J:
  		CHECK_CMDWIN;
  		win_goto_ver(FALSE, Prenum1);
  		break;
  
  // cursor to window above
      case 'k':
      case K_UP:
      case Ctrl_K:
  		CHECK_CMDWIN;
  		win_goto_ver(TRUE, Prenum1);
  		break;
  
  // cursor to left window
      case 'h':
      case K_LEFT:
      case Ctrl_H:
      case K_BS:
  		CHECK_CMDWIN;
  		win_goto_hor(TRUE, Prenum1);
  		break;
  
  // cursor to right window
      case 'l':
      case K_RIGHT:
      case Ctrl_L:
  		CHECK_CMDWIN;
  		win_goto_hor(FALSE, Prenum1);
  		break;
  
  // move window to new tab page
      case 'T':
  		CHECK_CMDWIN;
  		if (one_window())
  		    msg(_(m_onlyone));
  		else
  		{
  		    tabpage_T	*oldtab = curtab;
  		    tabpage_T	*newtab;
  
  		    // First create a new tab with the window, then go back to
  		    // the old tab and close the window there.
  		    wp = curwin;
  		    if (win_new_tabpage((int)Prenum) == OK
  						     && valid_tabpage(oldtab))
  		    {
  			newtab = curtab;
  			goto_tabpage_tp(oldtab, TRUE, TRUE);
  			if (curwin == wp)
  			    win_close(curwin, FALSE);
  			if (valid_tabpage(newtab))
  			    goto_tabpage_tp(newtab, TRUE, TRUE);
  		    }
  		}
  		break;
  
  // cursor to top-left window
      case 't':
      case Ctrl_T:
  		win_goto(firstwin);
  		break;
  
  // cursor to bottom-right window
      case 'b':
      case Ctrl_B:
  		win_goto(lastwin);
  		break;
  
  // cursor to last accessed (previous) window
      case 'p':
      case Ctrl_P:
  		if (!win_valid(prevwin))
  		    beep_flush();
  		else
  		    win_goto(prevwin);
  		break;
  
  // exchange current and next window
      case 'x':
      case Ctrl_X:
  		CHECK_CMDWIN;
  		win_exchange(Prenum);
  		break;
  
  // rotate windows downwards
      case Ctrl_R:
      case 'r':
  		CHECK_CMDWIN;
  		reset_VIsual_and_resel();	// stop Visual mode
  		win_rotate(FALSE, (int)Prenum1);    // downwards
  		break;
  
  // rotate windows upwards
      case 'R':
  		CHECK_CMDWIN;
  		reset_VIsual_and_resel();	// stop Visual mode
  		win_rotate(TRUE, (int)Prenum1);	    // upwards
  		break;
  
  // move window to the very top/bottom/left/right
      case 'K':
      case 'J':
      case 'H':
      case 'L':
  		CHECK_CMDWIN;
  		win_totop((int)Prenum,
  			((nchar == 'H' || nchar == 'L') ? WSP_VERT : 0)
  			| ((nchar == 'H' || nchar == 'K') ? WSP_TOP : WSP_BOT));
  		break;
  
  // make all windows the same height
      case '=':
  #ifdef FEAT_GUI
  		need_mouse_correct = TRUE;
  #endif
  		win_equal(NULL, FALSE, 'b');
  		break;
  
  // increase current window height
      case '+':
  #ifdef FEAT_GUI
  		need_mouse_correct = TRUE;
  #endif
  		win_setheight(curwin->w_height + (int)Prenum1);
  		break;
  
  // decrease current window height
      case '-':
  #ifdef FEAT_GUI
  		need_mouse_correct = TRUE;
  #endif
  		win_setheight(curwin->w_height - (int)Prenum1);
  		break;
  
  // set current window height
      case Ctrl__:
      case '_':
  #ifdef FEAT_GUI
  		need_mouse_correct = TRUE;
  #endif
  		win_setheight(Prenum ? (int)Prenum : 9999);
  		break;
  
  // increase current window width
      case '>':
  #ifdef FEAT_GUI
  		need_mouse_correct = TRUE;
  #endif
  		win_setwidth(curwin->w_width + (int)Prenum1);
  		break;
  
  // decrease current window width
      case '<':
  #ifdef FEAT_GUI
  		need_mouse_correct = TRUE;
  #endif
  		win_setwidth(curwin->w_width - (int)Prenum1);
  		break;
  
  // set current window width
      case '|':
  #ifdef FEAT_GUI
  		need_mouse_correct = TRUE;
  #endif
  		win_setwidth(Prenum != 0 ? (int)Prenum : 9999);
  		break;
  
  // jump to tag and split window if tag exists (in preview window)
  #if defined(FEAT_QUICKFIX)
      case '}':
  		CHECK_CMDWIN;
  		if (Prenum)
  		    g_do_tagpreview = Prenum;
  		else
  		    g_do_tagpreview = p_pvh;
  #endif
  		// FALLTHROUGH
      case ']':
      case Ctrl_RSB:
  		CHECK_CMDWIN;
  		// keep Visual mode, can select words to use as a tag
  		if (Prenum)
  		    postponed_split = Prenum;
  		else
  		    postponed_split = -1;
  #ifdef FEAT_QUICKFIX
  		if (nchar != '}')
  		    g_do_tagpreview = 0;
  #endif
  
  		// Execute the command right here, required when "wincmd ]"
  		// was used in a function.
  		do_nv_ident(Ctrl_RSB, NUL);
  		break;
  
  #ifdef FEAT_SEARCHPATH
  // edit file name under cursor in a new window
      case 'f':
      case 'F':
      case Ctrl_F:
  wingotofile:
  		CHECK_CMDWIN;
  
  		ptr = grab_file_name(Prenum1, &lnum);
  		if (ptr != NULL)
  		{
  		    tabpage_T	*oldtab = curtab;
  		    win_T	*oldwin = curwin;
  # ifdef FEAT_GUI
  		    need_mouse_correct = TRUE;
  # endif
  		    setpcmark();
  		    if (win_split(0, 0) == OK)
  		    {
  			RESET_BINDING(curwin);
  			if (do_ecmd(0, ptr, NULL, NULL, ECMD_LASTL,
  						   ECMD_HIDE, NULL) == FAIL)
  			{
  			    // Failed to open the file, close the window
  			    // opened for it.
  			    win_close(curwin, FALSE);
  			    goto_tabpage_win(oldtab, oldwin);
  			}
  			else if (nchar == 'F' && lnum >= 0)
  			{
  			    curwin->w_cursor.lnum = lnum;
  			    check_cursor_lnum();
  			    beginline(BL_SOL | BL_FIX);
  			}
  		    }
  		    vim_free(ptr);
  		}
  		break;
  #endif
  
  #ifdef FEAT_FIND_ID
  // Go to the first occurrence of the identifier under cursor along path in a
  // new window -- webb
      case 'i':			    // Go to any match
      case Ctrl_I:
  		type = FIND_ANY;
  		// FALLTHROUGH
      case 'd':			    // Go to definition, using 'define'
      case Ctrl_D:
  		CHECK_CMDWIN;
  		if ((len = find_ident_under_cursor(&ptr, FIND_IDENT)) == 0)
  		    break;
  		find_pattern_in_path(ptr, 0, len, TRUE,
  			Prenum == 0 ? TRUE : FALSE, type,
  			Prenum1, ACTION_SPLIT, (linenr_T)1, (linenr_T)MAXLNUM);
  		curwin->w_set_curswant = TRUE;
  		break;
  #endif
  
  // Quickfix window only: view the result under the cursor in a new split.
  #if defined(FEAT_QUICKFIX)
      case K_KENTER:
      case CAR:
  		if (bt_quickfix(curbuf))
  		    qf_view_result(TRUE);
  		break;
  #endif
  
  // CTRL-W g  extended commands
      case 'g':
      case Ctrl_G:
  		CHECK_CMDWIN;
  #ifdef USE_ON_FLY_SCROLL
  		dont_scroll = TRUE;		// disallow scrolling here
  #endif
  		++no_mapping;
  		++allow_keys;   // no mapping for xchar, but allow key codes
  		if (xchar == NUL)
  		    xchar = plain_vgetc();
  		LANGMAP_ADJUST(xchar, TRUE);
  		--no_mapping;
  		--allow_keys;
  #ifdef FEAT_CMDL_INFO
  		(void)add_to_showcmd(xchar);
  #endif
  		switch (xchar)
  		{
  #if defined(FEAT_QUICKFIX)
  		    case '}':
  			xchar = Ctrl_RSB;
  			if (Prenum)
  			    g_do_tagpreview = Prenum;
  			else
  			    g_do_tagpreview = p_pvh;
  #endif
  			// FALLTHROUGH
  		    case ']':
  		    case Ctrl_RSB:
  			// keep Visual mode, can select words to use as a tag
  			if (Prenum)
  			    postponed_split = Prenum;
  			else
  			    postponed_split = -1;
  
  			// Execute the command right here, required when
  			// "wincmd g}" was used in a function.
  			do_nv_ident('g', xchar);
  			break;
  
  #ifdef FEAT_SEARCHPATH
  		    case 'f':	    // CTRL-W gf: "gf" in a new tab page
  		    case 'F':	    // CTRL-W gF: "gF" in a new tab page
  			cmdmod.cmod_tab = tabpage_index(curtab) + 1;
  			nchar = xchar;
  			goto wingotofile;
  #endif
  		    case 't':	    // CTRL-W gt: go to next tab page
  			goto_tabpage((int)Prenum);
  			break;
  
  		    case 'T':	    // CTRL-W gT: go to previous tab page
  			goto_tabpage(-(int)Prenum1);
  			break;
  
  		    case TAB:	    // CTRL-W g<Tab>: go to last used tab page
  			if (goto_tabpage_lastused() == FAIL)
  			    beep_flush();
  			break;
  
  		    default:
  			beep_flush();
  			break;
  		}
  		break;
  
      default:	beep_flush();
  		break;
      }
  }
  
  /*
   * Figure out the address type for ":wincmd".
   */
      void
  get_wincmd_addr_type(char_u *arg, exarg_T *eap)
  {
      switch (*arg)
      {
      case 'S':
      case Ctrl_S:
      case 's':
      case Ctrl_N:
      case 'n':
      case 'j':
      case Ctrl_J:
      case 'k':
      case Ctrl_K:
      case 'T':
      case Ctrl_R:
      case 'r':
      case 'R':
      case 'K':
      case 'J':
      case '+':
      case '-':
      case Ctrl__:
      case '_':
      case '|':
      case ']':
      case Ctrl_RSB:
      case 'g':
      case Ctrl_G:
      case Ctrl_V:
      case 'v':
      case 'h':
      case Ctrl_H:
      case 'l':
      case Ctrl_L:
      case 'H':
      case 'L':
      case '>':
      case '<':
  #if defined(FEAT_QUICKFIX)
      case '}':
  #endif
  #ifdef FEAT_SEARCHPATH
      case 'f':
      case 'F':
      case Ctrl_F:
  #endif
  #ifdef FEAT_FIND_ID
      case 'i':
      case Ctrl_I:
      case 'd':
      case Ctrl_D:
  #endif
  		// window size or any count
  		eap->addr_type = ADDR_OTHER;
  		break;
  
      case Ctrl_HAT:
      case '^':
  		// buffer number
  		eap->addr_type = ADDR_BUFFERS;
  		break;
  
      case Ctrl_Q:
      case 'q':
      case Ctrl_C:
      case 'c':
      case Ctrl_O:
      case 'o':
      case Ctrl_W:
      case 'w':
      case 'W':
      case 'x':
      case Ctrl_X:
  		// window number
  		eap->addr_type = ADDR_WINDOWS;
  		break;
  
  #if defined(FEAT_QUICKFIX)
      case Ctrl_Z:
      case 'z':
      case 'P':
  #endif
      case 't':
      case Ctrl_T:
      case 'b':
      case Ctrl_B:
      case 'p':
      case Ctrl_P:
      case '=':
      case CAR:
  		// no count
  		eap->addr_type = ADDR_NONE;
  		break;
      }
  }
  
      static void
  cmd_with_count(
      char	*cmd,
      char_u	*bufp,
      size_t	bufsize,
      long	Prenum)
  {
      if (Prenum > 0)
  	vim_snprintf((char *)bufp, bufsize, "%s %ld", cmd, Prenum);
      else
  	STRCPY(bufp, cmd);
  }
  
  /*
   * If "split_disallowed" is set give an error and return FAIL.
   * Otherwise return OK.
   */
      static int
  check_split_disallowed()
  {
      if (split_disallowed > 0)
      {
  	emsg(_(e_cant_split_window_while_closing_another));
  	return FAIL;
      }
      if (curwin->w_buffer->b_locked_split)
      {
  	emsg(_(e_cannot_split_window_when_closing_buffer));
  	return FAIL;
      }
      return OK;
  }
  
  /*
   * split the current window, implements CTRL-W s and :split
   *
   * "size" is the height or width for the new window, 0 to use half of current
   * height or width.
   *
   * "flags":
   * WSP_ROOM: require enough room for new window
   * WSP_VERT: vertical split.
   * WSP_TOP:  open window at the top-left of the shell (help window).
   * WSP_BOT:  open window at the bottom-right of the shell (quickfix window).
   * WSP_HELP: creating the help window, keep layout snapshot
   *
   * return FAIL for failure, OK otherwise
   */
      int
  win_split(int size, int flags)
  {
      if (ERROR_IF_ANY_POPUP_WINDOW)
  	return FAIL;
  
      if (check_split_disallowed() == FAIL)
  	return FAIL;
  
      // When the ":tab" modifier was used open a new tab page instead.
      if (may_open_tabpage() == OK)
  	return OK;
  
      // Add flags from ":vertical", ":topleft" and ":botright".
      flags |= cmdmod.cmod_split;
      if ((flags & WSP_TOP) && (flags & WSP_BOT))
      {
  	emsg(_(e_cant_split_topleft_and_botright_at_the_same_time));
  	return FAIL;
      }
  
      // When creating the help window make a snapshot of the window layout.
      // Otherwise clear the snapshot, it's now invalid.
      if (flags & WSP_HELP)
  	make_snapshot(SNAP_HELP_IDX);
      else
  	clear_snapshot(curtab, SNAP_HELP_IDX);
  
      return win_split_ins(size, flags, NULL, 0);
  }
  
  /*
   * When "new_wp" is NULL: split the current window in two.
   * When "new_wp" is not NULL: insert this window at the far
   * top/left/right/bottom.
   * return FAIL for failure, OK otherwise
   */
      int
  win_split_ins(
      int		size,
      int		flags,
      win_T	*new_wp,
      int		dir)
  {
      win_T	*wp = new_wp;
      win_T	*oldwin;
      int		new_size = size;
      int		i;
      int		need_status = 0;
      int		do_equal = FALSE;
      int		needed;
      int		available;
      int		oldwin_height = 0;
      int		layout;
      frame_T	*frp, *curfrp, *frp2, *prevfrp;
      int		before;
      int		minheight;
      int		wmh1;
      int		did_set_fraction = FALSE;
  
      if (flags & WSP_TOP)
  	oldwin = firstwin;
      else if (flags & WSP_BOT)
  	oldwin = lastwin;
      else
  	oldwin = curwin;
  
      // add a status line when p_ls == 1 and splitting the first window
      if (ONE_WINDOW && p_ls == 1 && oldwin->w_status_height == 0)
      {
  	if (VISIBLE_HEIGHT(oldwin) <= p_wmh && new_wp == NULL)
  	{
  	    emsg(_(e_not_enough_room));
  	    return FAIL;
  	}
  	need_status = STATUS_HEIGHT;
      }
  
  #ifdef FEAT_GUI
      // May be needed for the scrollbars that are going to change.
      if (gui.in_use)
  	out_flush();
  #endif
  
      if (flags & WSP_VERT)
      {
  	int	wmw1;
  	int	minwidth;
  
  	layout = FR_ROW;
  
  	/*
  	 * Check if we are able to split the current window and compute its
  	 * width.
  	 */
  	// Current window requires at least 1 space.
  	wmw1 = (p_wmw == 0 ? 1 : p_wmw);
  	needed = wmw1 + 1;
  	if (flags & WSP_ROOM)
  	    needed += p_wiw - wmw1;
  	if (flags & (WSP_BOT | WSP_TOP))
  	{
  	    minwidth = frame_minwidth(topframe, NOWIN);
  	    available = topframe->fr_width;
  	    needed += minwidth;
  	}
  	else if (p_ea)
  	{
  	    minwidth = frame_minwidth(oldwin->w_frame, NOWIN);
  	    prevfrp = oldwin->w_frame;
  	    for (frp = oldwin->w_frame->fr_parent; frp != NULL;
  							frp = frp->fr_parent)
  	    {
  		if (frp->fr_layout == FR_ROW)
  		    FOR_ALL_FRAMES(frp2, frp->fr_child)
  			if (frp2 != prevfrp)
  			    minwidth += frame_minwidth(frp2, NOWIN);
  		prevfrp = frp;
  	    }
  	    available = topframe->fr_width;
  	    needed += minwidth;
  	}
  	else
  	{
  	    minwidth = frame_minwidth(oldwin->w_frame, NOWIN);
  	    available = oldwin->w_frame->fr_width;
  	    needed += minwidth;
  	}
  	if (available < needed && new_wp == NULL)
  	{
  	    emsg(_(e_not_enough_room));
  	    return FAIL;
  	}
  	if (new_size == 0)
  	    new_size = oldwin->w_width / 2;
  	if (new_size > available - minwidth - 1)
  	    new_size = available - minwidth - 1;
  	if (new_size < wmw1)
  	    new_size = wmw1;
  
  	// if it doesn't fit in the current window, need win_equal()
  	if (oldwin->w_width - new_size - 1 < p_wmw)
  	    do_equal = TRUE;
  
  	// We don't like to take lines for the new window from a
  	// 'winfixwidth' window.  Take them from a window to the left or right
  	// instead, if possible. Add one for the separator.
  	if (oldwin->w_p_wfw)
  	    win_setwidth_win(oldwin->w_width + new_size + 1, oldwin);
  
  	// Only make all windows the same width if one of them (except oldwin)
  	// is wider than one of the split windows.
  	if (!do_equal && p_ea && size == 0 && *p_ead != 'v'
  					 && oldwin->w_frame->fr_parent != NULL)
  	{
  	    frp = oldwin->w_frame->fr_parent->fr_child;
  	    while (frp != NULL)
  	    {
  		if (frp->fr_win != oldwin && frp->fr_win != NULL
  			&& (frp->fr_win->w_width > new_size
  			    || frp->fr_win->w_width > oldwin->w_width
  							      - new_size - 1))
  		{
  		    do_equal = TRUE;
  		    break;
  		}
  		frp = frp->fr_next;
  	    }
  	}
      }
      else
      {
  	layout = FR_COL;
  
  	/*
  	 * Check if we are able to split the current window and compute its
  	 * height.
  	 */
  	// Current window requires at least 1 space.
  	wmh1 = (p_wmh == 0 ? 1 : p_wmh) + WINBAR_HEIGHT(curwin);
  	needed = wmh1 + STATUS_HEIGHT;
  	if (flags & WSP_ROOM)
  	    needed += p_wh - wmh1;
  	if (flags & (WSP_BOT | WSP_TOP))
  	{
  	    minheight = frame_minheight(topframe, NOWIN) + need_status;
  	    available = topframe->fr_height;
  	    needed += minheight;
  	}
  	else if (p_ea)
  	{
  	    minheight = frame_minheight(oldwin->w_frame, NOWIN) + need_status;
  	    prevfrp = oldwin->w_frame;
  	    for (frp = oldwin->w_frame->fr_parent; frp != NULL;
  							frp = frp->fr_parent)
  	    {
  		if (frp->fr_layout == FR_COL)
  		    FOR_ALL_FRAMES(frp2, frp->fr_child)
  			if (frp2 != prevfrp)
  			    minheight += frame_minheight(frp2, NOWIN);
  		prevfrp = frp;
  	    }
  	    available = topframe->fr_height;
  	    needed += minheight;
  	}
  	else
  	{
  	    minheight = frame_minheight(oldwin->w_frame, NOWIN) + need_status;
  	    available = oldwin->w_frame->fr_height;
  	    needed += minheight;
  	}
  	if (available < needed && new_wp == NULL)
  	{
  	    emsg(_(e_not_enough_room));
  	    return FAIL;
  	}
  	oldwin_height = oldwin->w_height;
  	if (need_status)
  	{
  	    oldwin->w_status_height = STATUS_HEIGHT;
  	    oldwin_height -= STATUS_HEIGHT;
  	}
  	if (new_size == 0)
  	    new_size = oldwin_height / 2;
  	if (new_size > available - minheight - STATUS_HEIGHT)
  	    new_size = available - minheight - STATUS_HEIGHT;
  	if (new_size < wmh1)
  	    new_size = wmh1;
  
  	// if it doesn't fit in the current window, need win_equal()
  	if (oldwin_height - new_size - STATUS_HEIGHT < p_wmh)
  	    do_equal = TRUE;
  
  	// We don't like to take lines for the new window from a
  	// 'winfixheight' window.  Take them from a window above or below
  	// instead, if possible.
  	if (oldwin->w_p_wfh)
  	{
  	    // Set w_fraction now so that the cursor keeps the same relative
  	    // vertical position using the old height.
  	    set_fraction(oldwin);
  	    did_set_fraction = TRUE;
  
  	    win_setheight_win(oldwin->w_height + new_size + STATUS_HEIGHT,
  								      oldwin);
  	    oldwin_height = oldwin->w_height;
  	    if (need_status)
  		oldwin_height -= STATUS_HEIGHT;
  	}
  
  	// Only make all windows the same height if one of them (except oldwin)
  	// is higher than one of the split windows.
  	if (!do_equal && p_ea && size == 0 && *p_ead != 'h'
  	   && oldwin->w_frame->fr_parent != NULL)
  	{
  	    frp = oldwin->w_frame->fr_parent->fr_child;
  	    while (frp != NULL)
  	    {
  		if (frp->fr_win != oldwin && frp->fr_win != NULL
  			&& (frp->fr_win->w_height > new_size
  			    || frp->fr_win->w_height > oldwin_height - new_size
  							      - STATUS_HEIGHT))
  		{
  		    do_equal = TRUE;
  		    break;
  		}
  		frp = frp->fr_next;
  	    }
  	}
      }
  
      /*
       * allocate new window structure and link it in the window list
       */
      if ((flags & WSP_TOP) == 0
  	    && ((flags & WSP_BOT)
  		|| (flags & WSP_BELOW)
  		|| (!(flags & WSP_ABOVE)
  		    && ( (flags & WSP_VERT) ? p_spr : p_sb))))
      {
  	// new window below/right of current one
  	if (new_wp == NULL)
  	    wp = win_alloc(oldwin, FALSE);
  	else
  	    win_append(oldwin, wp);
      }
      else
      {
  	if (new_wp == NULL)
  	    wp = win_alloc(oldwin->w_prev, FALSE);
  	else
  	    win_append(oldwin->w_prev, wp);
      }
  
      if (new_wp == NULL)
      {
  	if (wp == NULL)
  	    return FAIL;
  
  	new_frame(wp);
  	if (wp->w_frame == NULL)
  	{
  	    win_free(wp, NULL);
  	    return FAIL;
  	}
  
  	// make the contents of the new window the same as the current one
  	win_init(wp, curwin, flags);
      }
  
      /*
       * Reorganise the tree of frames to insert the new window.
       */
      if (flags & (WSP_TOP | WSP_BOT))
      {
  	if ((topframe->fr_layout == FR_COL && (flags & WSP_VERT) == 0)
  	    || (topframe->fr_layout == FR_ROW && (flags & WSP_VERT) != 0))
  	{
  	    curfrp = topframe->fr_child;
  	    if (flags & WSP_BOT)
  		while (curfrp->fr_next != NULL)
  		    curfrp = curfrp->fr_next;
  	}
  	else
  	    curfrp = topframe;
  	before = (flags & WSP_TOP);
      }
      else
      {
  	curfrp = oldwin->w_frame;
  	if (flags & WSP_BELOW)
  	    before = FALSE;
  	else if (flags & WSP_ABOVE)
  	    before = TRUE;
  	else if (flags & WSP_VERT)
  	    before = !p_spr;
  	else
  	    before = !p_sb;
      }
      if (curfrp->fr_parent == NULL || curfrp->fr_parent->fr_layout != layout)
      {
  	// Need to create a new frame in the tree to make a branch.
  	frp = ALLOC_CLEAR_ONE(frame_T);
  	*frp = *curfrp;
  	curfrp->fr_layout = layout;
  	frp->fr_parent = curfrp;
  	frp->fr_next = NULL;
  	frp->fr_prev = NULL;
  	curfrp->fr_child = frp;
  	curfrp->fr_win = NULL;
  	curfrp = frp;
  	if (frp->fr_win != NULL)
  	    oldwin->w_frame = frp;
  	else
  	    FOR_ALL_FRAMES(frp, frp->fr_child)
  		frp->fr_parent = curfrp;
      }
  
      if (new_wp == NULL)
  	frp = wp->w_frame;
      else
  	frp = new_wp->w_frame;
      frp->fr_parent = curfrp->fr_parent;
  
      // Insert the new frame at the right place in the frame list.
      if (before)
  	frame_insert(curfrp, frp);
      else
  	frame_append(curfrp, frp);
  
      // Set w_fraction now so that the cursor keeps the same relative
      // vertical position.
      if (!did_set_fraction)
  	set_fraction(oldwin);
      wp->w_fraction = oldwin->w_fraction;
  
      if (flags & WSP_VERT)
      {
  	wp->w_p_scr = curwin->w_p_scr;
  
  	if (need_status)
  	{
  	    win_new_height(oldwin, oldwin->w_height - 1);
  	    oldwin->w_status_height = need_status;
  	}
  	if (flags & (WSP_TOP | WSP_BOT))
  	{
  	    // set height and row of new window to full height
  	    wp->w_winrow = tabline_height();
  	    win_new_height(wp, curfrp->fr_height - (p_ls > 0)
  							  - WINBAR_HEIGHT(wp));
  	    wp->w_status_height = (p_ls > 0);
  	}
  	else
  	{
  	    // height and row of new window is same as current window
  	    wp->w_winrow = oldwin->w_winrow;
  	    win_new_height(wp, VISIBLE_HEIGHT(oldwin));
  	    wp->w_status_height = oldwin->w_status_height;
  	}
  	frp->fr_height = curfrp->fr_height;
  
  	// "new_size" of the current window goes to the new window, use
  	// one column for the vertical separator
  	win_new_width(wp, new_size);
  	if (before)
  	    wp->w_vsep_width = 1;
  	else
  	{
  	    wp->w_vsep_width = oldwin->w_vsep_width;
  	    oldwin->w_vsep_width = 1;
  	}
  	if (flags & (WSP_TOP | WSP_BOT))
  	{
  	    if (flags & WSP_BOT)
  		frame_add_vsep(curfrp);
  	    // Set width of neighbor frame
  	    frame_new_width(curfrp, curfrp->fr_width
  		     - (new_size + ((flags & WSP_TOP) != 0)), flags & WSP_TOP,
  								       FALSE);
  	}
  	else
  	    win_new_width(oldwin, oldwin->w_width - (new_size + 1));
  	if (before)	// new window left of current one
  	{
  	    wp->w_wincol = oldwin->w_wincol;
  	    oldwin->w_wincol += new_size + 1;
  	}
  	else		// new window right of current one
  	    wp->w_wincol = oldwin->w_wincol + oldwin->w_width + 1;
  	frame_fix_width(oldwin);
  	frame_fix_width(wp);
      }
      else
      {
  	// width and column of new window is same as current window
  	if (flags & (WSP_TOP | WSP_BOT))
  	{
  	    wp->w_wincol = 0;
  	    win_new_width(wp, Columns);
  	    wp->w_vsep_width = 0;
  	}
  	else
  	{
  	    wp->w_wincol = oldwin->w_wincol;
  	    win_new_width(wp, oldwin->w_width);
  	    wp->w_vsep_width = oldwin->w_vsep_width;
  	}
  	frp->fr_width = curfrp->fr_width;
  
  	// "new_size" of the current window goes to the new window, use
  	// one row for the status line
  	win_new_height(wp, new_size);
  	if (flags & (WSP_TOP | WSP_BOT))
  	{
  	    int new_fr_height = curfrp->fr_height - new_size
  							  + WINBAR_HEIGHT(wp) ;
  
  	    if (!((flags & WSP_BOT) && p_ls == 0))
  		new_fr_height -= STATUS_HEIGHT;
  	    frame_new_height(curfrp, new_fr_height, flags & WSP_TOP, FALSE);
  	}
  	else
  	    win_new_height(oldwin, oldwin_height - (new_size + STATUS_HEIGHT));
  	if (before)	// new window above current one
  	{
  	    wp->w_winrow = oldwin->w_winrow;
  	    wp->w_status_height = STATUS_HEIGHT;
  	    oldwin->w_winrow += wp->w_height + STATUS_HEIGHT;
  	}
  	else		// new window below current one
  	{
  	    wp->w_winrow = oldwin->w_winrow + VISIBLE_HEIGHT(oldwin)
  							       + STATUS_HEIGHT;
  	    wp->w_status_height = oldwin->w_status_height;
  	    if (!(flags & WSP_BOT))
  		oldwin->w_status_height = STATUS_HEIGHT;
  	}
  	if (flags & WSP_BOT)
  	    frame_add_statusline(curfrp);
  	frame_fix_height(wp);
  	frame_fix_height(oldwin);
      }
  
      if (flags & (WSP_TOP | WSP_BOT))
  	(void)win_comp_pos();
  
       // Both windows need redrawing.  Update all status lines, in case they
       // show something related to the window count or position.
      redraw_win_later(wp, NOT_VALID);
      redraw_win_later(oldwin, NOT_VALID);
      status_redraw_all();
  
      if (need_status)
      {
  	msg_row = Rows - 1;
  	msg_col = sc_col;
  	msg_clr_eos_force();	// Old command/ruler may still be there
  	comp_col();
  	msg_row = Rows - 1;
  	msg_col = 0;	// put position back at start of line
      }
  
      /*
       * equalize the window sizes.
       */
      if (do_equal || dir != 0)
  	win_equal(wp, TRUE,
  		(flags & WSP_VERT) ? (dir == 'v' ? 'b' : 'h')
  		: dir == 'h' ? 'b' : 'v');
  
      // Don't change the window height/width to 'winheight' / 'winwidth' if a
      // size was given.
      if (flags & WSP_VERT)
      {
  	i = p_wiw;
  	if (size != 0)
  	    p_wiw = size;
  
  # ifdef FEAT_GUI
  	// When 'guioptions' includes 'L' or 'R' may have to add scrollbars.
  	if (gui.in_use)
  	    gui_init_which_components(NULL);
  # endif
      }
      else
      {
  	i = p_wh;
  	if (size != 0)
  	    p_wh = size;
      }
  
      // Keep same changelist position in new window.
      wp->w_changelistidx = oldwin->w_changelistidx;
  
      /*
       * make the new window the current window
       */
      (void)win_enter_ext(wp, WEE_TRIGGER_NEW_AUTOCMDS
  		    | WEE_TRIGGER_ENTER_AUTOCMDS | WEE_TRIGGER_LEAVE_AUTOCMDS);
      if (flags & WSP_VERT)
  	p_wiw = i;
      else
  	p_wh = i;
  
      return OK;
  }
  
  
  /*
   * Initialize window "newp" from window "oldp".
   * Used when splitting a window and when creating a new tab page.
   * The windows will both edit the same buffer.
   * WSP_NEWLOC may be specified in flags to prevent the location list from
   * being copied.
   */
      static void
  win_init(win_T *newp, win_T *oldp, int flags UNUSED)
  {
      int		i;
  
      newp->w_buffer = oldp->w_buffer;
  #ifdef FEAT_SYN_HL
      newp->w_s = &(oldp->w_buffer->b_s);
  #endif
      oldp->w_buffer->b_nwindows++;
      newp->w_cursor = oldp->w_cursor;
      newp->w_valid = 0;
      newp->w_curswant = oldp->w_curswant;
      newp->w_set_curswant = oldp->w_set_curswant;
      newp->w_topline = oldp->w_topline;
  #ifdef FEAT_DIFF
      newp->w_topfill = oldp->w_topfill;
  #endif
      newp->w_leftcol = oldp->w_leftcol;
      newp->w_pcmark = oldp->w_pcmark;
      newp->w_prev_pcmark = oldp->w_prev_pcmark;
      newp->w_alt_fnum = oldp->w_alt_fnum;
      newp->w_wrow = oldp->w_wrow;
      newp->w_fraction = oldp->w_fraction;
      newp->w_prev_fraction_row = oldp->w_prev_fraction_row;
      copy_jumplist(oldp, newp);
  #ifdef FEAT_QUICKFIX
      if (flags & WSP_NEWLOC)
      {
  	// Don't copy the location list.
  	newp->w_llist = NULL;
  	newp->w_llist_ref = NULL;
      }
      else
  	copy_loclist_stack(oldp, newp);
  #endif
      newp->w_localdir = (oldp->w_localdir == NULL)
  				    ? NULL : vim_strsave(oldp->w_localdir);
      newp->w_prevdir = (oldp->w_prevdir == NULL)
  				    ? NULL : vim_strsave(oldp->w_prevdir);
  
      // copy tagstack and folds
      for (i = 0; i < oldp->w_tagstacklen; i++)
      {
  	taggy_T	*tag = &newp->w_tagstack[i];
  	*tag = oldp->w_tagstack[i];
  	if (tag->tagname != NULL)
  	    tag->tagname = vim_strsave(tag->tagname);
  	if (tag->user_data != NULL)
  	    tag->user_data = vim_strsave(tag->user_data);
      }
      newp->w_tagstackidx = oldp->w_tagstackidx;
      newp->w_tagstacklen = oldp->w_tagstacklen;
  #ifdef FEAT_FOLDING
      copyFoldingState(oldp, newp);
  #endif
  
      win_init_some(newp, oldp);
  #ifdef FEAT_TERMINAL
      term_update_wincolor(newp);
  #endif
  }
  
  /*
   * Initialize window "newp" from window "old".
   * Only the essential things are copied.
   */
      static void
  win_init_some(win_T *newp, win_T *oldp)
  {
      // Use the same argument list.
      newp->w_alist = oldp->w_alist;
      ++newp->w_alist->al_refcount;
      newp->w_arg_idx = oldp->w_arg_idx;
  
      // copy options from existing window
      win_copy_options(oldp, newp);
  }
  
  /*
   * Return TRUE if "win" is a global popup or a popup in the current tab page.
   */
      int
  win_valid_popup(win_T *win UNUSED)
  {
  #ifdef FEAT_PROP_POPUP
      win_T	*wp;
  
      FOR_ALL_POPUPWINS(wp)
  	if (wp == win)
  	    return TRUE;
      FOR_ALL_POPUPWINS_IN_TAB(curtab, wp)
  	if (wp == win)
  	    return TRUE;
  #endif
      return FALSE;
  }
  
  /*
   * Check if "win" is a pointer to an existing window in the current tab page.
   */
      int
  win_valid(win_T *win)
  {
      win_T	*wp;
  
      if (win == NULL)
  	return FALSE;
      FOR_ALL_WINDOWS(wp)
  	if (wp == win)
  	    return TRUE;
      return win_valid_popup(win);
  }
  
  /*
   * Find window "id" in the current tab page.
   * Also find popup windows.
   * Return NULL if not found.
   */
      win_T *
  win_find_by_id(int id)
  {
      win_T   *wp;
  
      FOR_ALL_WINDOWS(wp)
  	if (wp->w_id == id)
  	    return wp;
  #ifdef FEAT_PROP_POPUP
      FOR_ALL_POPUPWINS(wp)
  	if (wp->w_id == id)
  	    return wp;
      FOR_ALL_POPUPWINS_IN_TAB(curtab, wp)
  	if (wp->w_id == id)
  	    return wp;
  #endif
      return NULL;
  }
  
  /*
   * Check if "win" is a pointer to an existing window in any tab page.
   */
      int
  win_valid_any_tab(win_T *win)
  {
      win_T	*wp;
      tabpage_T	*tp;
  
      if (win == NULL)
  	return FALSE;
      FOR_ALL_TABPAGES(tp)
      {
  	FOR_ALL_WINDOWS_IN_TAB(tp, wp)
  	{
  	    if (wp == win)
  		return TRUE;
  	}
  #ifdef FEAT_PROP_POPUP
  	FOR_ALL_POPUPWINS_IN_TAB(tp, wp)
  	    if (wp == win)
  		return TRUE;
  #endif
      }
      return win_valid_popup(win);
  }
  
  /*
   * Return the number of windows.
   */
      int
  win_count(void)
  {
      win_T	*wp;
      int		count = 0;
  
      FOR_ALL_WINDOWS(wp)
  	++count;
      return count;
  }
  
  /*
   * Make "count" windows on the screen.
   * Return actual number of windows on the screen.
   * Must be called when there is just one window, filling the whole screen
   * (excluding the command line).
   */
      int
  make_windows(
      int		count,
      int		vertical UNUSED)  // split windows vertically if TRUE
  {
      int		maxcount;
      int		todo;
  
      if (vertical)
      {
  	// Each window needs at least 'winminwidth' lines and a separator
  	// column.
  	maxcount = (curwin->w_width + curwin->w_vsep_width
  					     - (p_wiw - p_wmw)) / (p_wmw + 1);
      }
      else
      {
  	// Each window needs at least 'winminheight' lines and a status line.
  	maxcount = (VISIBLE_HEIGHT(curwin) + curwin->w_status_height
  				  - (p_wh - p_wmh)) / (p_wmh + STATUS_HEIGHT);
      }
  
      if (maxcount < 2)
  	maxcount = 2;
      if (count > maxcount)
  	count = maxcount;
  
      /*
       * add status line now, otherwise first window will be too big
       */
      if (count > 1)
  	last_status(TRUE);
  
      /*
       * Don't execute autocommands while creating the windows.  Must do that
       * when putting the buffers in the windows.
       */
      block_autocmds();
  
      // todo is number of windows left to create
      for (todo = count - 1; todo > 0; --todo)
  	if (vertical)
  	{
  	    if (win_split(curwin->w_width - (curwin->w_width - todo)
  			/ (todo + 1) - 1, WSP_VERT | WSP_ABOVE) == FAIL)
  		break;
  	}
  	else
  	{
  	    if (win_split(curwin->w_height - (curwin->w_height - todo
  			    * STATUS_HEIGHT) / (todo + 1)
  			- STATUS_HEIGHT, WSP_ABOVE) == FAIL)
  		break;
  	}
  
      unblock_autocmds();
  
      // return actual number of windows
      return (count - todo);
  }
  
  /*
   * Exchange current and next window
   */
      static void
  win_exchange(long Prenum)
  {
      frame_T	*frp;
      frame_T	*frp2;
      win_T	*wp;
      win_T	*wp2;
      int		temp;
  
      if (ERROR_IF_ANY_POPUP_WINDOW)
  	return;
      if (ONE_WINDOW)	    // just one window
      {
  	beep_flush();
  	return;
      }
  
  #ifdef FEAT_GUI
      need_mouse_correct = TRUE;
  #endif
  
      /*
       * find window to exchange with
       */
      if (Prenum)
      {
  	frp = curwin->w_frame->fr_parent->fr_child;
  	while (frp != NULL && --Prenum > 0)
  	    frp = frp->fr_next;
      }
      else if (curwin->w_frame->fr_next != NULL)	// Swap with next
  	frp = curwin->w_frame->fr_next;
      else    // Swap last window in row/col with previous
  	frp = curwin->w_frame->fr_prev;
  
      // We can only exchange a window with another window, not with a frame
      // containing windows.
      if (frp == NULL || frp->fr_win == NULL || frp->fr_win == curwin)
  	return;
      wp = frp->fr_win;
  
  /*
   * 1. remove curwin from the list. Remember after which window it was in wp2
   * 2. insert curwin before wp in the list
   * if wp != wp2
   *    3. remove wp from the list
   *    4. insert wp after wp2
   * 5. exchange the status line height and vsep width.
   */
      wp2 = curwin->w_prev;
      frp2 = curwin->w_frame->fr_prev;
      if (wp->w_prev != curwin)
      {
  	win_remove(curwin, NULL);
  	frame_remove(curwin->w_frame);
  	win_append(wp->w_prev, curwin);
  	frame_insert(frp, curwin->w_frame);
      }
      if (wp != wp2)
      {
  	win_remove(wp, NULL);
  	frame_remove(wp->w_frame);
  	win_append(wp2, wp);
  	if (frp2 == NULL)
  	    frame_insert(wp->w_frame->fr_parent->fr_child, wp->w_frame);
  	else
  	    frame_append(frp2, wp->w_frame);
      }
      temp = curwin->w_status_height;
      curwin->w_status_height = wp->w_status_height;
      wp->w_status_height = temp;
      temp = curwin->w_vsep_width;
      curwin->w_vsep_width = wp->w_vsep_width;
      wp->w_vsep_width = temp;
  
      frame_fix_height(curwin);
      frame_fix_height(wp);
      frame_fix_width(curwin);
      frame_fix_width(wp);
  
      (void)win_comp_pos();		// recompute window positions
  
      if (wp->w_buffer != curbuf)
  	reset_VIsual_and_resel();
      else if (VIsual_active)
  	wp->w_cursor = curwin->w_cursor;
  
      win_enter(wp, TRUE);
      redraw_all_later(NOT_VALID);
  }
  
  /*
   * rotate windows: if upwards TRUE the second window becomes the first one
   *		   if upwards FALSE the first window becomes the second one
   */
      static void
  win_rotate(int upwards, int count)
  {
      win_T	*wp1;
      win_T	*wp2;
      frame_T	*frp;
      int		n;
  
      if (ONE_WINDOW)		// nothing to do
      {
  	beep_flush();
  	return;
      }
  
  #ifdef FEAT_GUI
      need_mouse_correct = TRUE;
  #endif
  
      // Check if all frames in this row/col have one window.
      FOR_ALL_FRAMES(frp, curwin->w_frame->fr_parent->fr_child)
  	if (frp->fr_win == NULL)
  	{
  	    emsg(_(e_cannot_rotate_when_another_window_is_split));
  	    return;
  	}
  
      while (count--)
      {
  	if (upwards)		// first window becomes last window
  	{
  	    // remove first window/frame from the list
  	    frp = curwin->w_frame->fr_parent->fr_child;
  	    wp1 = frp->fr_win;
  	    win_remove(wp1, NULL);
  	    frame_remove(frp);
  
  	    // find last frame and append removed window/frame after it
  	    for ( ; frp->fr_next != NULL; frp = frp->fr_next)
  		;
  	    win_append(frp->fr_win, wp1);
  	    frame_append(frp, wp1->w_frame);
  
  	    wp2 = frp->fr_win;		// previously last window
  	}
  	else			// last window becomes first window
  	{
  	    // find last window/frame in the list and remove it
  	    for (frp = curwin->w_frame; frp->fr_next != NULL;
  							   frp = frp->fr_next)
  		;
  	    wp1 = frp->fr_win;
  	    wp2 = wp1->w_prev;		    // will become last window
  	    win_remove(wp1, NULL);
  	    frame_remove(frp);
  
  	    // append the removed window/frame before the first in the list
  	    win_append(frp->fr_parent->fr_child->fr_win->w_prev, wp1);
  	    frame_insert(frp->fr_parent->fr_child, frp);
  	}
  
  	// exchange status height and vsep width of old and new last window
  	n = wp2->w_status_height;
  	wp2->w_status_height = wp1->w_status_height;
  	wp1->w_status_height = n;
  	frame_fix_height(wp1);
  	frame_fix_height(wp2);
  	n = wp2->w_vsep_width;
  	wp2->w_vsep_width = wp1->w_vsep_width;
  	wp1->w_vsep_width = n;
  	frame_fix_width(wp1);
  	frame_fix_width(wp2);
  
  	// recompute w_winrow and w_wincol for all windows
  	(void)win_comp_pos();
      }
  
      redraw_all_later(NOT_VALID);
  }
  
  /*
   * Move the current window to the very top/bottom/left/right of the screen.
   */
      static void
  win_totop(int size, int flags)
  {
      int		dir;
      int		height = curwin->w_height;
  
      if (ONE_WINDOW)
      {
  	beep_flush();
  	return;
      }
      if (check_split_disallowed() == FAIL)
  	return;
  
      // Remove the window and frame from the tree of frames.
      (void)winframe_remove(curwin, &dir, NULL);
      win_remove(curwin, NULL);
      last_status(FALSE);	    // may need to remove last status line
      (void)win_comp_pos();   // recompute window positions
  
      // Split a window on the desired side and put the window there.
      (void)win_split_ins(size, flags, curwin, dir);
      if (!(flags & WSP_VERT))
      {
  	win_setheight(height);
  	if (p_ea)
  	    win_equal(curwin, TRUE, 'v');
      }
  
  #if defined(FEAT_GUI)
      // When 'guioptions' includes 'L' or 'R' may have to remove or add
      // scrollbars.  Have to update them anyway.
      gui_may_update_scrollbars();
  #endif
  }
  
  /*
   * Move window "win1" to below/right of "win2" and make "win1" the current
   * window.  Only works within the same frame!
   */
      void
  win_move_after(win_T *win1, win_T *win2)
  {
      int		height;
  
      // check if the arguments are reasonable
      if (win1 == win2)
  	return;
  
      // check if there is something to do
      if (win2->w_next != win1)
      {
  	if (win1->w_frame->fr_parent != win2->w_frame->fr_parent)
  	{
  	    iemsg("INTERNAL: trying to move a window into another frame");
  	    return;
  	}
  
  	// may need to move the status line/vertical separator of the last
  	// window
  	if (win1 == lastwin)
  	{
  	    height = win1->w_prev->w_status_height;
  	    win1->w_prev->w_status_height = win1->w_status_height;
  	    win1->w_status_height = height;
  	    if (win1->w_prev->w_vsep_width == 1)
  	    {
  		// Remove the vertical separator from the last-but-one window,
  		// add it to the last window.  Adjust the frame widths.
  		win1->w_prev->w_vsep_width = 0;
  		win1->w_prev->w_frame->fr_width -= 1;
  		win1->w_vsep_width = 1;
  		win1->w_frame->fr_width += 1;
  	    }
  	}
  	else if (win2 == lastwin)
  	{
  	    height = win1->w_status_height;
  	    win1->w_status_height = win2->w_status_height;
  	    win2->w_status_height = height;
  	    if (win1->w_vsep_width == 1)
  	    {
  		// Remove the vertical separator from win1, add it to the last
  		// window, win2.  Adjust the frame widths.
  		win2->w_vsep_width = 1;
  		win2->w_frame->fr_width += 1;
  		win1->w_vsep_width = 0;
  		win1->w_frame->fr_width -= 1;
  	    }
  	}
  	win_remove(win1, NULL);
  	frame_remove(win1->w_frame);
  	win_append(win2, win1);
  	frame_append(win2->w_frame, win1->w_frame);
  
  	(void)win_comp_pos();	// recompute w_winrow for all windows
  	redraw_later(NOT_VALID);
      }
      win_enter(win1, FALSE);
  }
  
  /*
   * Make all windows the same height.
   * 'next_curwin' will soon be the current window, make sure it has enough
   * rows.
   */
      void
  win_equal(
      win_T	*next_curwin,	// pointer to current window to be or NULL
      int		current,	// do only frame with current window
      int		dir)		// 'v' for vertically, 'h' for horizontally,
  				// 'b' for both, 0 for using p_ead
  {
      if (dir == 0)
  	dir = *p_ead;
      win_equal_rec(next_curwin == NULL ? curwin : next_curwin, current,
  		      topframe, dir, 0, tabline_height(),
  					   (int)Columns, topframe->fr_height);
  }
  
  /*
   * Set a frame to a new position and height, spreading the available room
   * equally over contained frames.
   * The window "next_curwin" (if not NULL) should at least get the size from
   * 'winheight' and 'winwidth' if possible.
   */
      static void
  win_equal_rec(
      win_T	*next_curwin,	// pointer to current window to be or NULL
      int		current,	// do only frame with current window
      frame_T	*topfr,		// frame to set size off
      int		dir,		// 'v', 'h' or 'b', see win_equal()
      int		col,		// horizontal position for frame
      int		row,		// vertical position for frame
      int		width,		// new width of frame
      int		height)		// new height of frame
  {
      int		n, m;
      int		extra_sep = 0;
      int		wincount, totwincount = 0;
      frame_T	*fr;
      int		next_curwin_size = 0;
      int		room = 0;
      int		new_size;
      int		has_next_curwin = 0;
      int		hnc;
  
      if (topfr->fr_layout == FR_LEAF)
      {
  	// Set the width/height of this frame.
  	// Redraw when size or position changes
  	if (topfr->fr_height != height || topfr->fr_win->w_winrow != row
  		|| topfr->fr_width != width || topfr->fr_win->w_wincol != col
  	   )
  	{
  	    topfr->fr_win->w_winrow = row;
  	    frame_new_height(topfr, height, FALSE, FALSE);
  	    topfr->fr_win->w_wincol = col;
  	    frame_new_width(topfr, width, FALSE, FALSE);
  	    redraw_all_later(NOT_VALID);
  	}
      }
      else if (topfr->fr_layout == FR_ROW)
      {
  	topfr->fr_width = width;
  	topfr->fr_height = height;
  
  	if (dir != 'v')			// equalize frame widths
  	{
  	    // Compute the maximum number of windows horizontally in this
  	    // frame.
  	    n = frame_minwidth(topfr, NOWIN);
  	    // add one for the rightmost window, it doesn't have a separator
  	    if (col + width == Columns)
  		extra_sep = 1;
  	    else
  		extra_sep = 0;
  	    totwincount = (n + extra_sep) / (p_wmw + 1);
  	    has_next_curwin = frame_has_win(topfr, next_curwin);
  
  	    /*
  	     * Compute width for "next_curwin" window and room available for
  	     * other windows.
  	     * "m" is the minimal width when counting p_wiw for "next_curwin".
  	     */
  	    m = frame_minwidth(topfr, next_curwin);
  	    room = width - m;
  	    if (room < 0)
  	    {
  		next_curwin_size = p_wiw + room;
  		room = 0;
  	    }
  	    else
  	    {
  		next_curwin_size = -1;
  		FOR_ALL_FRAMES(fr, topfr->fr_child)
  		{
  		    // If 'winfixwidth' set keep the window width if
  		    // possible.
  		    // Watch out for this window being the next_curwin.
  		    if (frame_fixed_width(fr))
  		    {
  			n = frame_minwidth(fr, NOWIN);
  			new_size = fr->fr_width;
  			if (frame_has_win(fr, next_curwin))
  			{
  			    room += p_wiw - p_wmw;
  			    next_curwin_size = 0;
  			    if (new_size < p_wiw)
  				new_size = p_wiw;
  			}
  			else
  			    // These windows don't use up room.
  			    totwincount -= (n + (fr->fr_next == NULL
  					      ? extra_sep : 0)) / (p_wmw + 1);
  			room -= new_size - n;
  			if (room < 0)
  			{
  			    new_size += room;
  			    room = 0;
  			}
  			fr->fr_newwidth = new_size;
  		    }
  		}
  		if (next_curwin_size == -1)
  		{
  		    if (!has_next_curwin)
  			next_curwin_size = 0;
  		    else if (totwincount > 1
  			    && (room + (totwincount - 2))
  						  / (totwincount - 1) > p_wiw)
  		    {
  			// Can make all windows wider than 'winwidth', spread
  			// the room equally.
  			next_curwin_size = (room + p_wiw
  					    + (totwincount - 1) * p_wmw
  					    + (totwincount - 1)) / totwincount;
  			room -= next_curwin_size - p_wiw;
  		    }
  		    else
  			next_curwin_size = p_wiw;
  		}
  	    }
  
  	    if (has_next_curwin)
  		--totwincount;		// don't count curwin
  	}
  
  	FOR_ALL_FRAMES(fr, topfr->fr_child)
  	{
  	    wincount = 1;
  	    if (fr->fr_next == NULL)
  		// last frame gets all that remains (avoid roundoff error)
  		new_size = width;
  	    else if (dir == 'v')
  		new_size = fr->fr_width;
  	    else if (frame_fixed_width(fr))
  	    {
  		new_size = fr->fr_newwidth;
  		wincount = 0;	    // doesn't count as a sizeable window
  	    }
  	    else
  	    {
  		// Compute the maximum number of windows horiz. in "fr".
  		n = frame_minwidth(fr, NOWIN);
  		wincount = (n + (fr->fr_next == NULL ? extra_sep : 0))
  								/ (p_wmw + 1);
  		m = frame_minwidth(fr, next_curwin);
  		if (has_next_curwin)
  		    hnc = frame_has_win(fr, next_curwin);
  		else
  		    hnc = FALSE;
  		if (hnc)	    // don't count next_curwin
  		    --wincount;
  		if (totwincount == 0)
  		    new_size = room;
  		else
  		    new_size = (wincount * room + ((unsigned)totwincount >> 1))
  								/ totwincount;
  		if (hnc)	    // add next_curwin size
  		{
  		    next_curwin_size -= p_wiw - (m - n);
  		    new_size += next_curwin_size;
  		    room -= new_size - next_curwin_size;
  		}
  		else
  		    room -= new_size;
  		new_size += n;
  	    }
  
  	    // Skip frame that is full width when splitting or closing a
  	    // window, unless equalizing all frames.
  	    if (!current || dir != 'v' || topfr->fr_parent != NULL
  		    || (new_size != fr->fr_width)
  		    || frame_has_win(fr, next_curwin))
  		win_equal_rec(next_curwin, current, fr, dir, col, row,
  							    new_size, height);
  	    col += new_size;
  	    width -= new_size;
  	    totwincount -= wincount;
  	}
      }
      else // topfr->fr_layout == FR_COL
      {
  	topfr->fr_width = width;
  	topfr->fr_height = height;
  
  	if (dir != 'h')			// equalize frame heights
  	{
  	    // Compute maximum number of windows vertically in this frame.
  	    n = frame_minheight(topfr, NOWIN);
  	    // add one for the bottom window if it doesn't have a statusline
  	    if (row + height == cmdline_row && p_ls == 0)
  		extra_sep = 1;
  	    else
  		extra_sep = 0;
  	    totwincount = (n + extra_sep) / (p_wmh + 1);
  	    has_next_curwin = frame_has_win(topfr, next_curwin);
  
  	    /*
  	     * Compute height for "next_curwin" window and room available for
  	     * other windows.
  	     * "m" is the minimal height when counting p_wh for "next_curwin".
  	     */
  	    m = frame_minheight(topfr, next_curwin);
  	    room = height - m;
  	    if (room < 0)
  	    {
  		// The room is less than 'winheight', use all space for the
  		// current window.
  		next_curwin_size = p_wh + room;
  		room = 0;
  	    }
  	    else
  	    {
  		next_curwin_size = -1;
  		FOR_ALL_FRAMES(fr, topfr->fr_child)
  		{
  		    // If 'winfixheight' set keep the window height if
  		    // possible.
  		    // Watch out for this window being the next_curwin.
  		    if (frame_fixed_height(fr))
  		    {
  			n = frame_minheight(fr, NOWIN);
  			new_size = fr->fr_height;
  			if (frame_has_win(fr, next_curwin))
  			{
  			    room += p_wh - p_wmh;
  			    next_curwin_size = 0;
  			    if (new_size < p_wh)
  				new_size = p_wh;
  			}
  			else
  			    // These windows don't use up room.
  			    totwincount -= (n + (fr->fr_next == NULL
  					      ? extra_sep : 0)) / (p_wmh + 1);
  			room -= new_size - n;
  			if (room < 0)
  			{
  			    new_size += room;
  			    room = 0;
  			}
  			fr->fr_newheight = new_size;
  		    }
  		}
  		if (next_curwin_size == -1)
  		{
  		    if (!has_next_curwin)
  			next_curwin_size = 0;
  		    else if (totwincount > 1
  			    && (room + (totwincount - 2))
  						   / (totwincount - 1) > p_wh)
  		    {
  			// can make all windows higher than 'winheight',
  			// spread the room equally.
  			next_curwin_size = (room + p_wh
  					   + (totwincount - 1) * p_wmh
  					   + (totwincount - 1)) / totwincount;
  			room -= next_curwin_size - p_wh;
  		    }
  		    else
  			next_curwin_size = p_wh;
  		}
  	    }
  
  	    if (has_next_curwin)
  		--totwincount;		// don't count curwin
  	}
  
  	FOR_ALL_FRAMES(fr, topfr->fr_child)
  	{
  	    wincount = 1;
  	    if (fr->fr_next == NULL)
  		// last frame gets all that remains (avoid roundoff error)
  		new_size = height;
  	    else if (dir == 'h')
  		new_size = fr->fr_height;
  	    else if (frame_fixed_height(fr))
  	    {
  		new_size = fr->fr_newheight;
  		wincount = 0;	    // doesn't count as a sizeable window
  	    }
  	    else
  	    {
  		// Compute the maximum number of windows vert. in "fr".
  		n = frame_minheight(fr, NOWIN);
  		wincount = (n + (fr->fr_next == NULL ? extra_sep : 0))
  								/ (p_wmh + 1);
  		m = frame_minheight(fr, next_curwin);
  		if (has_next_curwin)
  		    hnc = frame_has_win(fr, next_curwin);
  		else
  		    hnc = FALSE;
  		if (hnc)	    // don't count next_curwin
  		    --wincount;
  		if (totwincount == 0)
  		    new_size = room;
  		else
  		    new_size = (wincount * room + ((unsigned)totwincount >> 1))
  								/ totwincount;
  		if (hnc)	    // add next_curwin size
  		{
  		    next_curwin_size -= p_wh - (m - n);
  		    new_size += next_curwin_size;
  		    room -= new_size - next_curwin_size;
  		}
  		else
  		    room -= new_size;
  		new_size += n;
  	    }
  	    // Skip frame that is full width when splitting or closing a
  	    // window, unless equalizing all frames.
  	    if (!current || dir != 'h' || topfr->fr_parent != NULL
  		    || (new_size != fr->fr_height)
  		    || frame_has_win(fr, next_curwin))
  		win_equal_rec(next_curwin, current, fr, dir, col, row,
  							     width, new_size);
  	    row += new_size;
  	    height -= new_size;
  	    totwincount -= wincount;
  	}
      }
  }
  
  #ifdef FEAT_JOB_CHANNEL
      static void
  leaving_window(win_T *win)
  {
      // Only matters for a prompt window.
      if (!bt_prompt(win->w_buffer))
  	return;
  
      // When leaving a prompt window stop Insert mode and perhaps restart
      // it when entering that window again.
      win->w_buffer->b_prompt_insert = restart_edit;
      if (restart_edit != 0 && mode_displayed)
  	clear_cmdline = TRUE;		// unshow mode later
      restart_edit = NUL;
  
      // When leaving the window (or closing the window) was done from a
      // callback we need to break out of the Insert mode loop and restart Insert
      // mode when entering the window again.
      if (State & INSERT)
      {
  	stop_insert_mode = TRUE;
  	if (win->w_buffer->b_prompt_insert == NUL)
  	    win->w_buffer->b_prompt_insert = 'A';
      }
  }
  
      void
  entering_window(win_T *win)
  {
      // Only matters for a prompt window.
      if (!bt_prompt(win->w_buffer))
  	return;
  
      // When switching to a prompt buffer that was in Insert mode, don't stop
      // Insert mode, it may have been set in leaving_window().
      if (win->w_buffer->b_prompt_insert != NUL)
  	stop_insert_mode = FALSE;
  
      // When entering the prompt window restart Insert mode if we were in Insert
      // mode when we left it and not already in Insert mode.
      if ((State & INSERT) == 0)
  	restart_edit = win->w_buffer->b_prompt_insert;
  }
  #endif
  
      static void
  win_init_empty(win_T *wp)
  {
      redraw_win_later(wp, NOT_VALID);
      wp->w_lines_valid = 0;
      wp->w_cursor.lnum = 1;
      wp->w_curswant = wp->w_cursor.col = 0;
      wp->w_cursor.coladd = 0;
      wp->w_pcmark.lnum = 1;	// pcmark not cleared but set to line 1
      wp->w_pcmark.col = 0;
      wp->w_prev_pcmark.lnum = 0;
      wp->w_prev_pcmark.col = 0;
      wp->w_topline = 1;
  #ifdef FEAT_DIFF
      wp->w_topfill = 0;
  #endif
      wp->w_botline = 2;
  #if defined(FEAT_SYN_HL) || defined(FEAT_SPELL)
      wp->w_s = &wp->w_buffer->b_s;
  #endif
  #ifdef FEAT_TERMINAL
      term_reset_wincolor(wp);
  #endif
  }
  
  /*
   * Init the current window "curwin".
   * Called when a new file is being edited.
   */
      void
  curwin_init(void)
  {
      win_init_empty(curwin);
  }
  
  /*
   * Close all windows for buffer "buf".
   */
      void
  close_windows(
      buf_T	*buf,
      int		keep_curwin)	    // don't close "curwin"
  {
      win_T	*wp;
      tabpage_T   *tp, *nexttp;
      int		h = tabline_height();
      int		count = tabpage_index(NULL);
  
      ++RedrawingDisabled;
  
      for (wp = firstwin; wp != NULL && !ONE_WINDOW; )
      {
  	if (wp->w_buffer == buf && (!keep_curwin || wp != curwin)
  		&& !(wp->w_closing || wp->w_buffer->b_locked > 0))
  	{
  	    if (win_close(wp, FALSE) == FAIL)
  		// If closing the window fails give up, to avoid looping
  		// forever.
  		break;
  
  	    // Start all over, autocommands may change the window layout.
  	    wp = firstwin;
  	}
  	else
  	    wp = wp->w_next;
      }
  
      // Also check windows in other tab pages.
      for (tp = first_tabpage; tp != NULL; tp = nexttp)
      {
  	nexttp = tp->tp_next;
  	if (tp != curtab)
  	    FOR_ALL_WINDOWS_IN_TAB(tp, wp)
  		if (wp->w_buffer == buf
  		    && !(wp->w_closing || wp->w_buffer->b_locked > 0))
  		{
  		    win_close_othertab(wp, FALSE, tp);
  
  		    // Start all over, the tab page may be closed and
  		    // autocommands may change the window layout.
  		    nexttp = first_tabpage;
  		    break;
  		}
      }
  
      --RedrawingDisabled;
  
      if (count != tabpage_index(NULL))
  	apply_autocmds(EVENT_TABCLOSED, NULL, NULL, FALSE, curbuf);
  
      redraw_tabline = TRUE;
      if (h != tabline_height())
  	shell_new_rows();
  }
  
  /*
   * Return TRUE if the current window is the only window that exists (ignoring
   * "aucmd_win").
   * Returns FALSE if there is a window, possibly in another tab page.
   */
      static int
  last_window(void)
  {
      return (one_window() && first_tabpage->tp_next == NULL);
  }
  
  /*
   * Return TRUE if there is only one window other than "aucmd_win" in the
   * current tab page.
   */
      int
  one_window(void)
  {
      win_T	*wp;
      int		seen_one = FALSE;
  
      FOR_ALL_WINDOWS(wp)
      {
  	if (wp != aucmd_win)
  	{
  	    if (seen_one)
  		return FALSE;
  	    seen_one = TRUE;
  	}
      }
      return TRUE;
  }
  
  /*
   * Close the possibly last window in a tab page.
   * Returns TRUE when the window was closed already.
   */
      static int
  close_last_window_tabpage(
      win_T	*win,
      int		free_buf,
      tabpage_T   *prev_curtab)
  {
      if (ONE_WINDOW)
      {
  	buf_T	*old_curbuf = curbuf;
  
  	/*
  	 * Closing the last window in a tab page.  First go to another tab
  	 * page and then close the window and the tab page.  This avoids that
  	 * curwin and curtab are invalid while we are freeing memory, they may
  	 * be used in GUI events.
  	 * Don't trigger autocommands yet, they may use wrong values, so do
  	 * that below.
  	 */
  	goto_tabpage_tp(alt_tabpage(), FALSE, TRUE);
  	redraw_tabline = TRUE;
  
  	// Safety check: Autocommands may have closed the window when jumping
  	// to the other tab page.
  	if (valid_tabpage(prev_curtab) && prev_curtab->tp_firstwin == win)
  	{
  	    int	    h = tabline_height();
  
  	    win_close_othertab(win, free_buf, prev_curtab);
  	    if (h != tabline_height())
  		shell_new_rows();
  	}
  #ifdef FEAT_JOB_CHANNEL
  	entering_window(curwin);
  #endif
  	// Since goto_tabpage_tp above did not trigger *Enter autocommands, do
  	// that now.
  	apply_autocmds(EVENT_TABCLOSED, NULL, NULL, FALSE, curbuf);
  	apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
  	apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
  	if (old_curbuf != curbuf)
  	    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
  	return TRUE;
      }
      return FALSE;
  }
  
  /*
   * Close the buffer of "win" and unload it if "action" is DOBUF_UNLOAD.
   * "action" can also be zero (do nothing) or DOBUF_WIPE.
   * "abort_if_last" is passed to close_buffer(): abort closing if all other
   * windows are closed.
   */
      static void
  win_close_buffer(win_T *win, int action, int abort_if_last)
  {
  #ifdef FEAT_SYN_HL
      // Free independent synblock before the buffer is freed.
      if (win->w_buffer != NULL)
  	reset_synblock(win);
  #endif
  
  #ifdef FEAT_QUICKFIX
      // When a quickfix/location list window is closed and the buffer is
      // displayed in only one window, then unlist the buffer.
      if (win->w_buffer != NULL && bt_quickfix(win->w_buffer)
  					&& win->w_buffer->b_nwindows == 1)
  	win->w_buffer->b_p_bl = FALSE;
  #endif
  
      // Close the link to the buffer.
      if (win->w_buffer != NULL)
      {
  	bufref_T    bufref;
  
  	set_bufref(&bufref, curbuf);
  	win->w_closing = TRUE;
  	close_buffer(win, win->w_buffer, action, abort_if_last, FALSE);
  	if (win_valid_any_tab(win))
  	    win->w_closing = FALSE;
  	// Make sure curbuf is valid. It can become invalid if 'bufhidden' is
  	// "wipe".
  	if (!bufref_valid(&bufref))
  	    curbuf = firstbuf;
      }
  }
  
  /*
   * Close window "win".  Only works for the current tab page.
   * If "free_buf" is TRUE related buffer may be unloaded.
   *
   * Called by :quit, :close, :xit, :wq and findtag().
   * Returns FAIL when the window was not closed.
   */
      int
  win_close(win_T *win, int free_buf)
  {
      win_T	*wp;
      int		other_buffer = FALSE;
      int		close_curwin = FALSE;
      int		dir;
      int		help_window = FALSE;
      tabpage_T   *prev_curtab = curtab;
      frame_T	*win_frame = win->w_frame->fr_parent;
  #ifdef FEAT_DIFF
      int		had_diffmode = win->w_p_diff;
  #endif
  #ifdef MESSAGE_QUEUE
      int		did_decrement = FALSE;
  #endif
  
  #if defined(FEAT_TERMINAL) && defined(FEAT_PROP_POPUP)
      // Can close a popup window with a terminal if the job has finished.
      if (may_close_term_popup() == OK)
  	return OK;
  #endif
      if (ERROR_IF_ANY_POPUP_WINDOW)
  	return FAIL;
  
      if (last_window())
      {
  	emsg(_(e_cannot_close_last_window));
  	return FAIL;
      }
  
      if (win->w_closing || (win->w_buffer != NULL
  					       && win->w_buffer->b_locked > 0))
  	return FAIL; // window is already being closed
      if (win_unlisted(win))
      {
  	emsg(_(e_cannot_close_autocmd_or_popup_window));
  	return FAIL;
      }
      if ((firstwin == aucmd_win || lastwin == aucmd_win) && one_window())
      {
  	emsg(_(e_cannot_close_window_only_autocmd_window_would_remain));
  	return FAIL;
      }
  
      // When closing the last window in a tab page first go to another tab page
      // and then close the window and the tab page to avoid that curwin and
      // curtab are invalid while we are freeing memory.
      if (close_last_window_tabpage(win, free_buf, prev_curtab))
        return FAIL;
  
      // When closing the help window, try restoring a snapshot after closing
      // the window.  Otherwise clear the snapshot, it's now invalid.
      if (bt_help(win->w_buffer))
  	help_window = TRUE;
      else
  	clear_snapshot(curtab, SNAP_HELP_IDX);
  
      if (win == curwin)
      {
  #ifdef FEAT_JOB_CHANNEL
  	leaving_window(curwin);
  #endif
  	/*
  	 * Guess which window is going to be the new current window.
  	 * This may change because of the autocommands (sigh).
  	 */
  	wp = frame2win(win_altframe(win, NULL));
  
  	/*
  	 * Be careful: If autocommands delete the window or cause this window
  	 * to be the last one left, return now.
  	 */
  	if (wp->w_buffer != curbuf)
  	{
  	    other_buffer = TRUE;
  	    win->w_closing = TRUE;
  	    apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, FALSE, curbuf);
  	    if (!win_valid(win))
  		return FAIL;
  	    win->w_closing = FALSE;
  	    if (last_window())
  		return FAIL;
  	}
  	win->w_closing = TRUE;
  	apply_autocmds(EVENT_WINLEAVE, NULL, NULL, FALSE, curbuf);
  	if (!win_valid(win))
  	    return FAIL;
  	win->w_closing = FALSE;
  	if (last_window())
  	    return FAIL;
  #ifdef FEAT_EVAL
  	// autocmds may abort script processing
  	if (aborting())
  	    return FAIL;
  #endif
      }
  
  #ifdef FEAT_GUI
      // Avoid trouble with scrollbars that are going to be deleted in
      // win_free().
      if (gui.in_use)
  	out_flush();
  #endif
  
  #ifdef FEAT_PROP_POPUP
      if (popup_win_closed(win) && !win_valid(win))
  	return FAIL;
  #endif
  
      // Trigger WinClosed just before starting to free window-related resources.
      trigger_winclosed(win);
      // autocmd may have freed the window already.
      if (!win_valid_any_tab(win))
  	return OK;
  
      win_close_buffer(win, free_buf ? DOBUF_UNLOAD : 0, TRUE);
  
      if (only_one_window() && win_valid(win) && win->w_buffer == NULL
  	    && (last_window() || curtab != prev_curtab
  		|| close_last_window_tabpage(win, free_buf, prev_curtab)))
      {
  	// Autocommands have closed all windows, quit now.  Restore
  	// curwin->w_buffer, otherwise writing viminfo may fail.
  	if (curwin->w_buffer == NULL)
  	    curwin->w_buffer = curbuf;
  	getout(0);
      }
  
      // Autocommands may have moved to another tab page.
      if (curtab != prev_curtab && win_valid_any_tab(win)
  						      && win->w_buffer == NULL)
      {
  	// Need to close the window anyway, since the buffer is NULL.
  	win_close_othertab(win, FALSE, prev_curtab);
  	return FAIL;
      }
  
      // Autocommands may have closed the window already or closed the only
      // other window.
      if (!win_valid(win) || last_window()
  	    || close_last_window_tabpage(win, free_buf, prev_curtab))
  	return FAIL;
  
      // Now we are really going to close the window.  Disallow any autocommand
      // to split a window to avoid trouble.
      // Also bail out of parse_queued_messages() to avoid it tries to update the
      // screen.
      ++split_disallowed;
  #ifdef MESSAGE_QUEUE
      ++dont_parse_messages;
  #endif
  
      // Free the memory used for the window and get the window that received
      // the screen space.
      wp = win_free_mem(win, &dir, NULL);
  
      // Make sure curwin isn't invalid.  It can cause severe trouble when
      // printing an error message.  For win_equal() curbuf needs to be valid
      // too.
      if (win == curwin)
      {
  	curwin = wp;
  #ifdef FEAT_QUICKFIX
  	if (wp->w_p_pvw || bt_quickfix(wp->w_buffer))
  	{
  	    /*
  	     * If the cursor goes to the preview or the quickfix window, try
  	     * finding another window to go to.
  	     */
  	    for (;;)
  	    {
  		if (wp->w_next == NULL)
  		    wp = firstwin;
  		else
  		    wp = wp->w_next;
  		if (wp == curwin)
  		    break;
  		if (!wp->w_p_pvw && !bt_quickfix(wp->w_buffer))
  		{
  		    curwin = wp;
  		    break;
  		}
  	    }
  	}
  #endif
  	curbuf = curwin->w_buffer;
  	close_curwin = TRUE;
  
  	// The cursor position may be invalid if the buffer changed after last
  	// using the window.
  	check_cursor();
      }
      if (p_ea && (*p_ead == 'b' || *p_ead == dir))
  	// If the frame of the closed window contains the new current window,
  	// only resize that frame.  Otherwise resize all windows.
  	win_equal(curwin, curwin->w_frame->fr_parent == win_frame, dir);
      else
  	win_comp_pos();
      if (close_curwin)
      {
  	// Pass WEE_ALLOW_PARSE_MESSAGES to decrement dont_parse_messages
  	// before autocommands.
  #ifdef MESSAGE_QUEUE
  	did_decrement =
  #else
  	(void)
  #endif
  	    win_enter_ext(wp,
  		WEE_CURWIN_INVALID | WEE_TRIGGER_ENTER_AUTOCMDS
  		      | WEE_TRIGGER_LEAVE_AUTOCMDS | WEE_ALLOW_PARSE_MESSAGES);
  	if (other_buffer)
  	    // careful: after this wp and win may be invalid!
  	    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
      }
  
      --split_disallowed;
  #ifdef MESSAGE_QUEUE
      if (!did_decrement)
  	--dont_parse_messages;
  #endif
  
      /*
       * If last window has a status line now and we don't want one,
       * remove the status line.
       */
      last_status(FALSE);
  
      // After closing the help window, try restoring the window layout from
      // before it was opened.
      if (help_window)
  	restore_snapshot(SNAP_HELP_IDX, close_curwin);
  
  #ifdef FEAT_DIFF
      // If the window had 'diff' set and now there is only one window left in
      // the tab page with 'diff' set, and "closeoff" is in 'diffopt', then
      // execute ":diffoff!".
      if (diffopt_closeoff() && had_diffmode && curtab == prev_curtab)
      {
  	int	diffcount = 0;
  	win_T	*dwin;
  
  	FOR_ALL_WINDOWS(dwin)
  	    if (dwin->w_p_diff)
  		++diffcount;
  	if (diffcount == 1)
  	    do_cmdline_cmd((char_u *)"diffoff!");
      }
  #endif
  
  #if defined(FEAT_GUI)
      // When 'guioptions' includes 'L' or 'R' may have to remove scrollbars.
      if (gui.in_use && !win_hasvertsplit())
  	gui_init_which_components(NULL);
  #endif
  
      redraw_all_later(NOT_VALID);
      return OK;
  }
  
      static void
  trigger_winclosed(win_T *win)
  {
      static int	recursive = FALSE;
      char_u	winid[NUMBUFLEN];
  
      if (recursive)
  	return;
      recursive = TRUE;
      vim_snprintf((char *)winid, sizeof(winid), "%i", win->w_id);
      apply_autocmds(EVENT_WINCLOSED, winid, winid, FALSE, win->w_buffer);
      recursive = FALSE;
  }
  
  /*
   * Close window "win" in tab page "tp", which is not the current tab page.
   * This may be the last window in that tab page and result in closing the tab,
   * thus "tp" may become invalid!
   * Caller must check if buffer is hidden and whether the tabline needs to be
   * updated.
   */
      void
  win_close_othertab(win_T *win, int free_buf, tabpage_T *tp)
  {
      win_T	*wp;
      int		dir;
      tabpage_T   *ptp = NULL;
      int		free_tp = FALSE;
  
      // Get here with win->w_buffer == NULL when win_close() detects the tab
      // page changed.
      if (win->w_closing || (win->w_buffer != NULL
  					       && win->w_buffer->b_locked > 0))
  	return; // window is already being closed
  
      // Trigger WinClosed just before starting to free window-related resources.
      trigger_winclosed(win);
      // autocmd may have freed the window already.
      if (!win_valid_any_tab(win))
  	return;
  
      if (win->w_buffer != NULL)
  	// Close the link to the buffer.
  	close_buffer(win, win->w_buffer, free_buf ? DOBUF_UNLOAD : 0,
  								 FALSE, FALSE);
  
      // Careful: Autocommands may have closed the tab page or made it the
      // current tab page.
      for (ptp = first_tabpage; ptp != NULL && ptp != tp; ptp = ptp->tp_next)
  	;
      if (ptp == NULL || tp == curtab)
      {
  	// If the buffer was removed from the window we have to give it any
  	// buffer.
  	if (win_valid_any_tab(win) && win->w_buffer == NULL)
  	{
  	    win->w_buffer = firstbuf;
  	    ++firstbuf->b_nwindows;
  	    win_init_empty(win);
  	}
  	return;
      }
  
      // Autocommands may have closed the window already.
      for (wp = tp->tp_firstwin; wp != NULL && wp != win; wp = wp->w_next)
  	;
      if (wp == NULL)
  	return;
  
      // When closing the last window in a tab page remove the tab page.
      if (tp->tp_firstwin == tp->tp_lastwin)
      {
  	if (tp == first_tabpage)
  	    first_tabpage = tp->tp_next;
  	else
  	{
  	    for (ptp = first_tabpage; ptp != NULL && ptp->tp_next != tp;
  							   ptp = ptp->tp_next)
  		;
  	    if (ptp == NULL)
  	    {
  		internal_error("win_close_othertab()");
  		return;
  	    }
  	    ptp->tp_next = tp->tp_next;
  	}
  	free_tp = TRUE;
      }
  
      // Free the memory used for the window.
      win_free_mem(win, &dir, tp);
  
      if (free_tp)
  	free_tabpage(tp);
  }
  
  /*
   * Free the memory used for a window.
   * Returns a pointer to the window that got the freed up space.
   */
      static win_T *
  win_free_mem(
      win_T	*win,
      int		*dirp,		// set to 'v' or 'h' for direction if 'ea'
      tabpage_T	*tp)		// tab page "win" is in, NULL for current
  {
      frame_T	*frp;
      win_T	*wp;
      tabpage_T	*win_tp = tp == NULL ? curtab : tp;
  
      // Remove the window and its frame from the tree of frames.
      frp = win->w_frame;
      wp = winframe_remove(win, dirp, tp);
      vim_free(frp);
      win_free(win, tp);
  
      // When deleting the current window in the tab, select a new current
      // window.
      if (win == win_tp->tp_curwin)
  	win_tp->tp_curwin = wp;
  
      return wp;
  }
  
  #if defined(EXITFREE) || defined(PROTO)
      void
  win_free_all(void)
  {
      int		dummy;
  
  #ifdef FEAT_CMDWIN
      // avoid an error for switching tabpage with the cmdline window open
      cmdwin_type = 0;
  #endif
      while (first_tabpage->tp_next != NULL)
  	tabpage_close(TRUE);
  
      if (aucmd_win != NULL)
      {
  	(void)win_free_mem(aucmd_win, &dummy, NULL);
  	aucmd_win = NULL;
      }
  
      while (firstwin != NULL)
  	(void)win_free_mem(firstwin, &dummy, NULL);
  
      // No window should be used after this. Set curwin to NULL to crash
      // instead of using freed memory.
      curwin = NULL;
  }
  #endif
  
  /*
   * Remove a window and its frame from the tree of frames.
   * Returns a pointer to the window that got the freed up space.
   */
      win_T *
  winframe_remove(
      win_T	*win,
      int		*dirp UNUSED,	// set to 'v' or 'h' for direction if 'ea'
      tabpage_T	*tp)		// tab page "win" is in, NULL for current
  {
      frame_T	*frp, *frp2, *frp3;
      frame_T	*frp_close = win->w_frame;
      win_T	*wp;
  
      /*
       * If there is only one window there is nothing to remove.
       */
      if (tp == NULL ? ONE_WINDOW : tp->tp_firstwin == tp->tp_lastwin)
  	return NULL;
  
      /*
       * Remove the window from its frame.
       */
      frp2 = win_altframe(win, tp);
      wp = frame2win(frp2);
  
      // Remove this frame from the list of frames.
      frame_remove(frp_close);
  
      if (frp_close->fr_parent->fr_layout == FR_COL)
      {
  	// When 'winfixheight' is set, try to find another frame in the column
  	// (as close to the closed frame as possible) to distribute the height
  	// to.
  	if (frp2->fr_win != NULL && frp2->fr_win->w_p_wfh)
  	{
  	    frp = frp_close->fr_prev;
  	    frp3 = frp_close->fr_next;
  	    while (frp != NULL || frp3 != NULL)
  	    {
  		if (frp != NULL)
  		{
  		    if (!frame_fixed_height(frp))
  		    {
  			frp2 = frp;
  			wp = frame2win(frp2);
  			break;
  		    }
  		    frp = frp->fr_prev;
  		}
  		if (frp3 != NULL)
  		{
  		    if (frp3->fr_win != NULL && !frp3->fr_win->w_p_wfh)
  		    {
  			frp2 = frp3;
  			wp = frp3->fr_win;
  			break;
  		    }
  		    frp3 = frp3->fr_next;
  		}
  	    }
  	}
  	frame_new_height(frp2, frp2->fr_height + frp_close->fr_height,
  			    frp2 == frp_close->fr_next ? TRUE : FALSE, FALSE);
  	*dirp = 'v';
      }
      else
      {
  	// When 'winfixwidth' is set, try to find another frame in the column
  	// (as close to the closed frame as possible) to distribute the width
  	// to.
  	if (frp2->fr_win != NULL && frp2->fr_win->w_p_wfw)
  	{
  	    frp = frp_close->fr_prev;
  	    frp3 = frp_close->fr_next;
  	    while (frp != NULL || frp3 != NULL)
  	    {
  		if (frp != NULL)
  		{
  		    if (!frame_fixed_width(frp))
  		    {
  			frp2 = frp;
  			wp = frame2win(frp2);
  			break;
  		    }
  		    frp = frp->fr_prev;
  		}
  		if (frp3 != NULL)
  		{
  		    if (frp3->fr_win != NULL && !frp3->fr_win->w_p_wfw)
  		    {
  			frp2 = frp3;
  			wp = frp3->fr_win;
  			break;
  		    }
  		    frp3 = frp3->fr_next;
  		}
  	    }
  	}
  	frame_new_width(frp2, frp2->fr_width + frp_close->fr_width,
  			    frp2 == frp_close->fr_next ? TRUE : FALSE, FALSE);
  	*dirp = 'h';
      }
  
      // If rows/columns go to a window below/right its positions need to be
      // updated.  Can only be done after the sizes have been updated.
      if (frp2 == frp_close->fr_next)
      {
  	int row = win->w_winrow;
  	int col = win->w_wincol;
  
  	frame_comp_pos(frp2, &row, &col);
      }
  
      if (frp2->fr_next == NULL && frp2->fr_prev == NULL)
      {
  	// There is no other frame in this list, move its info to the parent
  	// and remove it.
  	frp2->fr_parent->fr_layout = frp2->fr_layout;
  	frp2->fr_parent->fr_child = frp2->fr_child;
  	FOR_ALL_FRAMES(frp, frp2->fr_child)
  	    frp->fr_parent = frp2->fr_parent;
  	frp2->fr_parent->fr_win = frp2->fr_win;
  	if (frp2->fr_win != NULL)
  	    frp2->fr_win->w_frame = frp2->fr_parent;
  	frp = frp2->fr_parent;
  	if (topframe->fr_child == frp2)
  	    topframe->fr_child = frp;
  	vim_free(frp2);
  
  	frp2 = frp->fr_parent;
  	if (frp2 != NULL && frp2->fr_layout == frp->fr_layout)
  	{
  	    // The frame above the parent has the same layout, have to merge
  	    // the frames into this list.
  	    if (frp2->fr_child == frp)
  		frp2->fr_child = frp->fr_child;
  	    frp->fr_child->fr_prev = frp->fr_prev;
  	    if (frp->fr_prev != NULL)
  		frp->fr_prev->fr_next = frp->fr_child;
  	    for (frp3 = frp->fr_child; ; frp3 = frp3->fr_next)
  	    {
  		frp3->fr_parent = frp2;
  		if (frp3->fr_next == NULL)
  		{
  		    frp3->fr_next = frp->fr_next;
  		    if (frp->fr_next != NULL)
  			frp->fr_next->fr_prev = frp3;
  		    break;
  		}
  	    }
  	    if (topframe->fr_child == frp)
  		topframe->fr_child = frp2;
  	    vim_free(frp);
  	}
      }
  
      return wp;
  }
  
  /*
   * Return a pointer to the frame that will receive the empty screen space that
   * is left over after "win" is closed.
   *
   * If 'splitbelow' or 'splitright' is set, the space goes above or to the left
   * by default.  Otherwise, the free space goes below or to the right.  The
   * result is that opening a window and then immediately closing it will
   * preserve the initial window layout.  The 'wfh' and 'wfw' settings are
   * respected when possible.
   */
      static frame_T *
  win_altframe(
      win_T	*win,
      tabpage_T	*tp)		// tab page "win" is in, NULL for current
  {
      frame_T	*frp;
      frame_T	*other_fr, *target_fr;
  
      if (tp == NULL ? ONE_WINDOW : tp->tp_firstwin == tp->tp_lastwin)
  	return alt_tabpage()->tp_curwin->w_frame;
  
      frp = win->w_frame;
  
      if (frp->fr_prev == NULL)
  	return frp->fr_next;
      if (frp->fr_next == NULL)
  	return frp->fr_prev;
  
      // By default the next window will get the space that was abandoned by this
      // window
      target_fr = frp->fr_next;
      other_fr  = frp->fr_prev;
  
      // If this is part of a column of windows and 'splitbelow' is true then the
      // previous window will get the space.
      if (frp->fr_parent != NULL && frp->fr_parent->fr_layout == FR_COL && p_sb)
      {
  	target_fr = frp->fr_prev;
  	other_fr  = frp->fr_next;
      }
  
      // If this is part of a row of windows, and 'splitright' is true then the
      // previous window will get the space.
      if (frp->fr_parent != NULL && frp->fr_parent->fr_layout == FR_ROW && p_spr)
      {
  	target_fr = frp->fr_prev;
  	other_fr  = frp->fr_next;
      }
  
      // If 'wfh' or 'wfw' is set for the target and not for the alternate
      // window, reverse the selection.
      if (frp->fr_parent != NULL && frp->fr_parent->fr_layout == FR_ROW)
      {
  	if (frame_fixed_width(target_fr) && !frame_fixed_width(other_fr))
  	    target_fr = other_fr;
      }
      else
      {
  	if (frame_fixed_height(target_fr) && !frame_fixed_height(other_fr))
  	    target_fr = other_fr;
      }
  
      return target_fr;
  }
  
  /*
   * Return the tabpage that will be used if the current one is closed.
   */
      static tabpage_T *
  alt_tabpage(void)
  {
      tabpage_T	*tp;
  
      // Use the next tab page if possible.
      if (curtab->tp_next != NULL)
  	return curtab->tp_next;
  
      // Find the last but one tab page.
      for (tp = first_tabpage; tp->tp_next != curtab; tp = tp->tp_next)
  	;
      return tp;
  }
  
  /*
   * Find the left-upper window in frame "frp".
   */
      static win_T *
  frame2win(frame_T *frp)
  {
      while (frp->fr_win == NULL)
  	frp = frp->fr_child;
      return frp->fr_win;
  }
  
  /*
   * Return TRUE if frame "frp" contains window "wp".
   */
      static int
  frame_has_win(frame_T *frp, win_T *wp)
  {
      frame_T	*p;
  
      if (frp->fr_layout == FR_LEAF)
  	return frp->fr_win == wp;
  
      FOR_ALL_FRAMES(p, frp->fr_child)
  	if (frame_has_win(p, wp))
  	    return TRUE;
      return FALSE;
  }
  
  /*
   * Set a new height for a frame.  Recursively sets the height for contained
   * frames and windows.  Caller must take care of positions.
   */
      static void
  frame_new_height(
      frame_T	*topfrp,
      int		height,
      int		topfirst,	// resize topmost contained frame first
      int		wfh)		// obey 'winfixheight' when there is a choice;
  				// may cause the height not to be set
  {
      frame_T	*frp;
      int		extra_lines;
      int		h;
  
      if (topfrp->fr_win != NULL)
      {
  	// Simple case: just one window.
  	win_new_height(topfrp->fr_win,
  				    height - topfrp->fr_win->w_status_height
  					      - WINBAR_HEIGHT(topfrp->fr_win));
      }
      else if (topfrp->fr_layout == FR_ROW)
      {
  	do
  	{
  	    // All frames in this row get the same new height.
  	    FOR_ALL_FRAMES(frp, topfrp->fr_child)
  	    {
  		frame_new_height(frp, height, topfirst, wfh);
  		if (frp->fr_height > height)
  		{
  		    // Could not fit the windows, make the whole row higher.
  		    height = frp->fr_height;
  		    break;
  		}
  	    }
  	}
  	while (frp != NULL);
      }
      else    // fr_layout == FR_COL
      {
  	// Complicated case: Resize a column of frames.  Resize the bottom
  	// frame first, frames above that when needed.
  
  	frp = topfrp->fr_child;
  	if (wfh)
  	    // Advance past frames with one window with 'wfh' set.
  	    while (frame_fixed_height(frp))
  	    {
  		frp = frp->fr_next;
  		if (frp == NULL)
  		    return;	    // no frame without 'wfh', give up
  	    }
  	if (!topfirst)
  	{
  	    // Find the bottom frame of this column
  	    while (frp->fr_next != NULL)
  		frp = frp->fr_next;
  	    if (wfh)
  		// Advance back for frames with one window with 'wfh' set.
  		while (frame_fixed_height(frp))
  		    frp = frp->fr_prev;
  	}
  
  	extra_lines = height - topfrp->fr_height;
  	if (extra_lines < 0)
  	{
  	    // reduce height of contained frames, bottom or top frame first
  	    while (frp != NULL)
  	    {
  		h = frame_minheight(frp, NULL);
  		if (frp->fr_height + extra_lines < h)
  		{
  		    extra_lines += frp->fr_height - h;
  		    frame_new_height(frp, h, topfirst, wfh);
  		}
  		else
  		{
  		    frame_new_height(frp, frp->fr_height + extra_lines,
  							       topfirst, wfh);
  		    break;
  		}
  		if (topfirst)
  		{
  		    do
  			frp = frp->fr_next;
  		    while (wfh && frp != NULL && frame_fixed_height(frp));
  		}
  		else
  		{
  		    do
  			frp = frp->fr_prev;
  		    while (wfh && frp != NULL && frame_fixed_height(frp));
  		}
  		// Increase "height" if we could not reduce enough frames.
  		if (frp == NULL)
  		    height -= extra_lines;
  	    }
  	}
  	else if (extra_lines > 0)
  	{
  	    // increase height of bottom or top frame
  	    frame_new_height(frp, frp->fr_height + extra_lines, topfirst, wfh);
  	}
      }
      topfrp->fr_height = height;
  }
  
  /*
   * Return TRUE if height of frame "frp" should not be changed because of
   * the 'winfixheight' option.
   */
      static int
  frame_fixed_height(frame_T *frp)
  {
      // frame with one window: fixed height if 'winfixheight' set.
      if (frp->fr_win != NULL)
  	return frp->fr_win->w_p_wfh;
  
      if (frp->fr_layout == FR_ROW)
      {
  	// The frame is fixed height if one of the frames in the row is fixed
  	// height.
  	FOR_ALL_FRAMES(frp, frp->fr_child)
  	    if (frame_fixed_height(frp))
  		return TRUE;
  	return FALSE;
      }
  
      // frp->fr_layout == FR_COL: The frame is fixed height if all of the
      // frames in the row are fixed height.
      FOR_ALL_FRAMES(frp, frp->fr_child)
  	if (!frame_fixed_height(frp))
  	    return FALSE;
      return TRUE;
  }
  
  /*
   * Return TRUE if width of frame "frp" should not be changed because of
   * the 'winfixwidth' option.
   */
      static int
  frame_fixed_width(frame_T *frp)
  {
      // frame with one window: fixed width if 'winfixwidth' set.
      if (frp->fr_win != NULL)
  	return frp->fr_win->w_p_wfw;
  
      if (frp->fr_layout == FR_COL)
      {
  	// The frame is fixed width if one of the frames in the row is fixed
  	// width.
  	FOR_ALL_FRAMES(frp, frp->fr_child)
  	    if (frame_fixed_width(frp))
  		return TRUE;
  	return FALSE;
      }
  
      // frp->fr_layout == FR_ROW: The frame is fixed width if all of the
      // frames in the row are fixed width.
      FOR_ALL_FRAMES(frp, frp->fr_child)
  	if (!frame_fixed_width(frp))
  	    return FALSE;
      return TRUE;
  }
  
  /*
   * Add a status line to windows at the bottom of "frp".
   * Note: Does not check if there is room!
   */
      static void
  frame_add_statusline(frame_T *frp)
  {
      win_T	*wp;
  
      if (frp->fr_layout == FR_LEAF)
      {
  	wp = frp->fr_win;
  	if (wp->w_status_height == 0)
  	{
  	    if (wp->w_height > 0)	// don't make it negative
  		--wp->w_height;
  	    wp->w_status_height = STATUS_HEIGHT;
  	}
      }
      else if (frp->fr_layout == FR_ROW)
      {
  	// Handle all the frames in the row.
  	FOR_ALL_FRAMES(frp, frp->fr_child)
  	    frame_add_statusline(frp);
      }
      else // frp->fr_layout == FR_COL
      {
  	// Only need to handle the last frame in the column.
  	for (frp = frp->fr_child; frp->fr_next != NULL; frp = frp->fr_next)
  	    ;
  	frame_add_statusline(frp);
      }
  }
  
  /*
   * Set width of a frame.  Handles recursively going through contained frames.
   * May remove separator line for windows at the right side (for win_close()).
   */
      static void
  frame_new_width(
      frame_T	*topfrp,
      int		width,
      int		leftfirst,	// resize leftmost contained frame first
      int		wfw)		// obey 'winfixwidth' when there is a choice;
  				// may cause the width not to be set
  {
      frame_T	*frp;
      int		extra_cols;
      int		w;
      win_T	*wp;
  
      if (topfrp->fr_layout == FR_LEAF)
      {
  	// Simple case: just one window.
  	wp = topfrp->fr_win;
  	// Find out if there are any windows right of this one.
  	for (frp = topfrp; frp->fr_parent != NULL; frp = frp->fr_parent)
  	    if (frp->fr_parent->fr_layout == FR_ROW && frp->fr_next != NULL)
  		break;
  	if (frp->fr_parent == NULL)
  	    wp->w_vsep_width = 0;
  	win_new_width(wp, width - wp->w_vsep_width);
      }
      else if (topfrp->fr_layout == FR_COL)
      {
  	do
  	{
  	    // All frames in this column get the same new width.
  	    FOR_ALL_FRAMES(frp, topfrp->fr_child)
  	    {
  		frame_new_width(frp, width, leftfirst, wfw);
  		if (frp->fr_width > width)
  		{
  		    // Could not fit the windows, make whole column wider.
  		    width = frp->fr_width;
  		    break;
  		}
  	    }
  	} while (frp != NULL);
      }
      else    // fr_layout == FR_ROW
      {
  	// Complicated case: Resize a row of frames.  Resize the rightmost
  	// frame first, frames left of it when needed.
  
  	frp = topfrp->fr_child;
  	if (wfw)
  	    // Advance past frames with one window with 'wfw' set.
  	    while (frame_fixed_width(frp))
  	    {
  		frp = frp->fr_next;
  		if (frp == NULL)
  		    return;	    // no frame without 'wfw', give up
  	    }
  	if (!leftfirst)
  	{
  	    // Find the rightmost frame of this row
  	    while (frp->fr_next != NULL)
  		frp = frp->fr_next;
  	    if (wfw)
  		// Advance back for frames with one window with 'wfw' set.
  		while (frame_fixed_width(frp))
  		    frp = frp->fr_prev;
  	}
  
  	extra_cols = width - topfrp->fr_width;
  	if (extra_cols < 0)
  	{
  	    // reduce frame width, rightmost frame first
  	    while (frp != NULL)
  	    {
  		w = frame_minwidth(frp, NULL);
  		if (frp->fr_width + extra_cols < w)
  		{
  		    extra_cols += frp->fr_width - w;
  		    frame_new_width(frp, w, leftfirst, wfw);
  		}
  		else
  		{
  		    frame_new_width(frp, frp->fr_width + extra_cols,
  							      leftfirst, wfw);
  		    break;
  		}
  		if (leftfirst)
  		{
  		    do
  			frp = frp->fr_next;
  		    while (wfw && frp != NULL && frame_fixed_width(frp));
  		}
  		else
  		{
  		    do
  			frp = frp->fr_prev;
  		    while (wfw && frp != NULL && frame_fixed_width(frp));
  		}
  		// Increase "width" if we could not reduce enough frames.
  		if (frp == NULL)
  		    width -= extra_cols;
  	    }
  	}
  	else if (extra_cols > 0)
  	{
  	    // increase width of rightmost frame
  	    frame_new_width(frp, frp->fr_width + extra_cols, leftfirst, wfw);
  	}
      }
      topfrp->fr_width = width;
  }
  
  /*
   * Add the vertical separator to windows at the right side of "frp".
   * Note: Does not check if there is room!
   */
      static void
  frame_add_vsep(frame_T *frp)
  {
      win_T	*wp;
  
      if (frp->fr_layout == FR_LEAF)
      {
  	wp = frp->fr_win;
  	if (wp->w_vsep_width == 0)
  	{
  	    if (wp->w_width > 0)	// don't make it negative
  		--wp->w_width;
  	    wp->w_vsep_width = 1;
  	}
      }
      else if (frp->fr_layout == FR_COL)
      {
  	// Handle all the frames in the column.
  	FOR_ALL_FRAMES(frp, frp->fr_child)
  	    frame_add_vsep(frp);
      }
      else // frp->fr_layout == FR_ROW
      {
  	// Only need to handle the last frame in the row.
  	frp = frp->fr_child;
  	while (frp->fr_next != NULL)
  	    frp = frp->fr_next;
  	frame_add_vsep(frp);
      }
  }
  
  /*
   * Set frame width from the window it contains.
   */
      static void
  frame_fix_width(win_T *wp)
  {
      wp->w_frame->fr_width = wp->w_width + wp->w_vsep_width;
  }
  
  /*
   * Set frame height from the window it contains.
   */
      static void
  frame_fix_height(win_T *wp)
  {
      wp->w_frame->fr_height = VISIBLE_HEIGHT(wp) + wp->w_status_height;
  }
  
  /*
   * Compute the minimal height for frame "topfrp".
   * Uses the 'winminheight' option.
   * When "next_curwin" isn't NULL, use p_wh for this window.
   * When "next_curwin" is NOWIN, don't use at least one line for the current
   * window.
   */
      static int
  frame_minheight(frame_T *topfrp, win_T *next_curwin)
  {
      frame_T	*frp;
      int		m;
      int		n;
  
      if (topfrp->fr_win != NULL)
      {
  	if (topfrp->fr_win == next_curwin)
  	    m = p_wh + topfrp->fr_win->w_status_height;
  	else
  	{
  	    // window: minimal height of the window plus status line
  	    m = p_wmh + topfrp->fr_win->w_status_height;
  	    if (topfrp->fr_win == curwin && next_curwin == NULL)
  	    {
  		// Current window is minimal one line high and WinBar is
  		// visible.
  		if (p_wmh == 0)
  		    ++m;
  		m += WINBAR_HEIGHT(curwin);
  	    }
  	}
      }
      else if (topfrp->fr_layout == FR_ROW)
      {
  	// get the minimal height from each frame in this row
  	m = 0;
  	FOR_ALL_FRAMES(frp, topfrp->fr_child)
  	{
  	    n = frame_minheight(frp, next_curwin);
  	    if (n > m)
  		m = n;
  	}
      }
      else
      {
  	// Add up the minimal heights for all frames in this column.
  	m = 0;
  	FOR_ALL_FRAMES(frp, topfrp->fr_child)
  	    m += frame_minheight(frp, next_curwin);
      }
  
      return m;
  }
  
  /*
   * Compute the minimal width for frame "topfrp".
   * When "next_curwin" isn't NULL, use p_wiw for this window.
   * When "next_curwin" is NOWIN, don't use at least one column for the current
   * window.
   */
      static int
  frame_minwidth(
      frame_T	*topfrp,
      win_T	*next_curwin)	// use p_wh and p_wiw for next_curwin
  {
      frame_T	*frp;
      int		m, n;
  
      if (topfrp->fr_win != NULL)
      {
  	if (topfrp->fr_win == next_curwin)
  	    m = p_wiw + topfrp->fr_win->w_vsep_width;
  	else
  	{
  	    // window: minimal width of the window plus separator column
  	    m = p_wmw + topfrp->fr_win->w_vsep_width;
  	    // Current window is minimal one column wide
  	    if (p_wmw == 0 && topfrp->fr_win == curwin && next_curwin == NULL)
  		++m;
  	}
      }
      else if (topfrp->fr_layout == FR_COL)
      {
  	// get the minimal width from each frame in this column
  	m = 0;
  	FOR_ALL_FRAMES(frp, topfrp->fr_child)
  	{
  	    n = frame_minwidth(frp, next_curwin);
  	    if (n > m)
  		m = n;
  	}
      }
      else
      {
  	// Add up the minimal widths for all frames in this row.
  	m = 0;
  	FOR_ALL_FRAMES(frp, topfrp->fr_child)
  	    m += frame_minwidth(frp, next_curwin);
      }
  
      return m;
  }
  
  
  /*
   * Try to close all windows except current one.
   * Buffers in the other windows become hidden if 'hidden' is set, or '!' is
   * used and the buffer was modified.
   *
   * Used by ":bdel" and ":only".
   */
      void
  close_others(
      int		message,
      int		forceit)	    // always hide all other windows
  {
      win_T	*wp;
      win_T	*nextwp;
      int		r;
  
      if (one_window())
      {
  	if (message && !autocmd_busy)
  	    msg(_(m_onlyone));
  	return;
      }
  
      // Be very careful here: autocommands may change the window layout.
      for (wp = firstwin; win_valid(wp); wp = nextwp)
      {
  	nextwp = wp->w_next;
  	if (wp != curwin)		// don't close current window
  	{
  
  	    // Check if it's allowed to abandon this window
  	    r = can_abandon(wp->w_buffer, forceit);
  	    if (!win_valid(wp))		// autocommands messed wp up
  	    {
  		nextwp = firstwin;
  		continue;
  	    }
  	    if (!r)
  	    {
  #if defined(FEAT_GUI_DIALOG) || defined(FEAT_CON_DIALOG)
  		if (message && (p_confirm
  			     || (cmdmod.cmod_flags & CMOD_CONFIRM)) && p_write)
  		{
  		    dialog_changed(wp->w_buffer, FALSE);
  		    if (!win_valid(wp))		// autocommands messed wp up
  		    {
  			nextwp = firstwin;
  			continue;
  		    }
  		}
  		if (bufIsChanged(wp->w_buffer))
  #endif
  		    continue;
  	    }
  	    win_close(wp, !buf_hide(wp->w_buffer)
  					       && !bufIsChanged(wp->w_buffer));
  	}
      }
  
      if (message && !ONE_WINDOW)
  	emsg(_(e_other_window_contains_changes));
  }
  
  /*
   * Allocate the first window and put an empty buffer in it.
   * Called from main().
   * Return FAIL when something goes wrong (out of memory).
   */
      int
  win_alloc_first(void)
  {
      if (win_alloc_firstwin(NULL) == FAIL)
  	return FAIL;
  
      first_tabpage = alloc_tabpage();
      if (first_tabpage == NULL)
  	return FAIL;
      first_tabpage->tp_topframe = topframe;
      curtab = first_tabpage;
      curtab->tp_firstwin = firstwin;
      curtab->tp_lastwin = lastwin;
      curtab->tp_curwin = curwin;
  
      return OK;
  }
  
  /*
   * Allocate and init a window that is not a regular window.
   * This can only be done after the first window is fully initialized, thus it
   * can't be in win_alloc_first().
   */
      win_T *
  win_alloc_popup_win(void)
  {
      win_T *wp;
  
      wp = win_alloc(NULL, TRUE);
      if (wp != NULL)
      {
  	// We need to initialize options with something, using the current
  	// window makes most sense.
  	win_init_some(wp, curwin);
  
  	RESET_BINDING(wp);
  	new_frame(wp);
      }
      return wp;
  }
  
  /*
   * Initialize window "wp" to display buffer "buf".
   */
      void
  win_init_popup_win(win_T *wp, buf_T *buf)
  {
      wp->w_buffer = buf;
      ++buf->b_nwindows;
      win_init_empty(wp); // set cursor and topline to safe values
  
      // Make sure w_localdir and globaldir are NULL to avoid a chdir() in
      // win_enter_ext().
      VIM_CLEAR(wp->w_localdir);
  }
  
  /*
   * Allocate the first window or the first window in a new tab page.
   * When "oldwin" is NULL create an empty buffer for it.
   * When "oldwin" is not NULL copy info from it to the new window.
   * Return FAIL when something goes wrong (out of memory).
   */
      static int
  win_alloc_firstwin(win_T *oldwin)
  {
      curwin = win_alloc(NULL, FALSE);
      if (oldwin == NULL)
      {
  	// Very first window, need to create an empty buffer for it and
  	// initialize from scratch.
  	curbuf = buflist_new(NULL, NULL, 1L, BLN_LISTED);
  	if (curwin == NULL || curbuf == NULL)
  	    return FAIL;
  	curwin->w_buffer = curbuf;
  #ifdef FEAT_SYN_HL
  	curwin->w_s = &(curbuf->b_s);
  #endif
  	curbuf->b_nwindows = 1;	// there is one window
  	curwin->w_alist = &global_alist;
  	curwin_init();		// init current window
      }
      else
      {
  	// First window in new tab page, initialize it from "oldwin".
  	win_init(curwin, oldwin, 0);
  
  	// We don't want cursor- and scroll-binding in the first window.
  	RESET_BINDING(curwin);
      }
  
      new_frame(curwin);
      if (curwin->w_frame == NULL)
  	return FAIL;
      topframe = curwin->w_frame;
      topframe->fr_width = Columns;
      topframe->fr_height = Rows - p_ch;
  
      return OK;
  }
  
  /*
   * Create a frame for window "wp".
   */
      static void
  new_frame(win_T *wp)
  {
      frame_T *frp = ALLOC_CLEAR_ONE(frame_T);
  
      wp->w_frame = frp;
      if (frp != NULL)
      {
  	frp->fr_layout = FR_LEAF;
  	frp->fr_win = wp;
      }
  }
  
  /*
   * Initialize the window and frame size to the maximum.
   */
      void
  win_init_size(void)
  {
      firstwin->w_height = ROWS_AVAIL;
      topframe->fr_height = ROWS_AVAIL;
      firstwin->w_width = Columns;
      topframe->fr_width = Columns;
  }
  
  /*
   * Allocate a new tabpage_T and init the values.
   * Returns NULL when out of memory.
   */
      static tabpage_T *
  alloc_tabpage(void)
  {
      tabpage_T	*tp;
  # ifdef FEAT_GUI
      int		i;
  # endif
  
  
      tp = ALLOC_CLEAR_ONE(tabpage_T);
      if (tp == NULL)
  	return NULL;
  
  # ifdef FEAT_EVAL
      // init t: variables
      tp->tp_vars = dict_alloc();
      if (tp->tp_vars == NULL)
      {
  	vim_free(tp);
  	return NULL;
      }
      init_var_dict(tp->tp_vars, &tp->tp_winvar, VAR_SCOPE);
  # endif
  
  # ifdef FEAT_GUI
      for (i = 0; i < 3; i++)
  	tp->tp_prev_which_scrollbars[i] = -1;
  # endif
  # ifdef FEAT_DIFF
      tp->tp_diff_invalid = TRUE;
  # endif
      tp->tp_ch_used = p_ch;
  
      return tp;
  }
  
      void
  free_tabpage(tabpage_T *tp)
  {
      int idx;
  
  # ifdef FEAT_DIFF
      diff_clear(tp);
  # endif
  # ifdef FEAT_PROP_POPUP
      while (tp->tp_first_popupwin != NULL)
  	popup_close_tabpage(tp, tp->tp_first_popupwin->w_id, TRUE);
  #endif
      for (idx = 0; idx < SNAP_COUNT; ++idx)
  	clear_snapshot(tp, idx);
  #ifdef FEAT_EVAL
      vars_clear(&tp->tp_vars->dv_hashtab);	// free all t: variables
      hash_init(&tp->tp_vars->dv_hashtab);
      unref_var_dict(tp->tp_vars);
  #endif
  
      if (tp == lastused_tabpage)
  	lastused_tabpage = NULL;
  
      vim_free(tp->tp_localdir);
      vim_free(tp->tp_prevdir);
  
  #ifdef FEAT_PYTHON
      python_tabpage_free(tp);
  #endif
  
  #ifdef FEAT_PYTHON3
      python3_tabpage_free(tp);
  #endif
  
      vim_free(tp);
  }
  
  /*
   * Create a new Tab page with one window.
   * It will edit the current buffer, like after ":split".
   * When "after" is 0 put it just after the current Tab page.
   * Otherwise put it just before tab page "after".
   * Return FAIL or OK.
   */
      int
  win_new_tabpage(int after)
  {
      tabpage_T	*tp = curtab;
      tabpage_T	*prev_tp = curtab;
      tabpage_T	*newtp;
      int		n;
  
  #ifdef FEAT_CMDWIN
      if (cmdwin_type != 0)
      {
  	emsg(_(e_invalid_in_cmdline_window));
  	return FAIL;
      }
  #endif
  
      newtp = alloc_tabpage();
      if (newtp == NULL)
  	return FAIL;
  
      // Remember the current windows in this Tab page.
      if (leave_tabpage(curbuf, TRUE) == FAIL)
      {
  	vim_free(newtp);
  	return FAIL;
      }
      curtab = newtp;
  
      newtp->tp_localdir = (tp->tp_localdir == NULL)
  				    ? NULL : vim_strsave(tp->tp_localdir);
      // Create a new empty window.
      if (win_alloc_firstwin(tp->tp_curwin) == OK)
      {
  	// Make the new Tab page the new topframe.
  	if (after == 1)
  	{
  	    // New tab page becomes the first one.
  	    newtp->tp_next = first_tabpage;
  	    first_tabpage = newtp;
  	}
  	else
  	{
  	    if (after > 0)
  	    {
  		// Put new tab page before tab page "after".
  		n = 2;
  		for (tp = first_tabpage; tp->tp_next != NULL
  					       && n < after; tp = tp->tp_next)
  		    ++n;
  	    }
  	    newtp->tp_next = tp->tp_next;
  	    tp->tp_next = newtp;
  	}
  	newtp->tp_firstwin = newtp->tp_lastwin = newtp->tp_curwin = curwin;
  
  	win_init_size();
  	firstwin->w_winrow = tabline_height();
  	win_comp_scroll(curwin);
  
  	newtp->tp_topframe = topframe;
  	last_status(FALSE);
  
  	lastused_tabpage = prev_tp;
  
  #if defined(FEAT_GUI)
  	// When 'guioptions' includes 'L' or 'R' may have to remove or add
  	// scrollbars.  Have to update them anyway.
  	gui_may_update_scrollbars();
  #endif
  #ifdef FEAT_JOB_CHANNEL
  	entering_window(curwin);
  #endif
  
  	redraw_all_later(NOT_VALID);
  	apply_autocmds(EVENT_WINNEW, NULL, NULL, FALSE, curbuf);
  	apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
  	apply_autocmds(EVENT_TABNEW, NULL, NULL, FALSE, curbuf);
  	apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
  	return OK;
      }
  
      // Failed, get back the previous Tab page
      enter_tabpage(curtab, curbuf, TRUE, TRUE);
      return FAIL;
  }
  
  /*
   * Open a new tab page if ":tab cmd" was used.  It will edit the same buffer,
   * like with ":split".
   * Returns OK if a new tab page was created, FAIL otherwise.
   */
      static int
  may_open_tabpage(void)
  {
      int		n = (cmdmod.cmod_tab == 0)
  				       ? postponed_split_tab : cmdmod.cmod_tab;
  
      if (n != 0)
      {
  	cmdmod.cmod_tab = 0;	    // reset it to avoid doing it twice
  	postponed_split_tab = 0;
  	return win_new_tabpage(n);
      }
      return FAIL;
  }
  
  /*
   * Create up to "maxcount" tabpages with empty windows.
   * Returns the number of resulting tab pages.
   */
      int
  make_tabpages(int maxcount)
  {
      int		count = maxcount;
      int		todo;
  
      // Limit to 'tabpagemax' tabs.
      if (count > p_tpm)
  	count = p_tpm;
  
      /*
       * Don't execute autocommands while creating the tab pages.  Must do that
       * when putting the buffers in the windows.
       */
      block_autocmds();
  
      for (todo = count - 1; todo > 0; --todo)
  	if (win_new_tabpage(0) == FAIL)
  	    break;
  
      unblock_autocmds();
  
      // return actual number of tab pages
      return (count - todo);
  }
  
  /*
   * Return TRUE when "tpc" points to a valid tab page.
   */
      int
  valid_tabpage(tabpage_T *tpc)
  {
      tabpage_T	*tp;
  
      FOR_ALL_TABPAGES(tp)
  	if (tp == tpc)
  	    return TRUE;
      return FALSE;
  }
  
  /*
   * Return TRUE when "tpc" points to a valid tab page and at least one window is
   * valid.
   */
      int
  valid_tabpage_win(tabpage_T *tpc)
  {
      tabpage_T	*tp;
      win_T	*wp;
  
      FOR_ALL_TABPAGES(tp)
      {
  	if (tp == tpc)
  	{
  	    FOR_ALL_WINDOWS_IN_TAB(tp, wp)
  	    {
  		if (win_valid_any_tab(wp))
  		    return TRUE;
  	    }
  	    return FALSE;
  	}
      }
      // shouldn't happen
      return FALSE;
  }
  
  /*
   * Close tabpage "tab", assuming it has no windows in it.
   * There must be another tabpage or this will crash.
   */
      void
  close_tabpage(tabpage_T *tab)
  {
      tabpage_T	*ptp;
  
      if (tab == first_tabpage)
      {
  	first_tabpage = tab->tp_next;
  	ptp = first_tabpage;
      }
      else
      {
  	for (ptp = first_tabpage; ptp != NULL && ptp->tp_next != tab;
  							    ptp = ptp->tp_next)
  	    ;
  	assert(ptp != NULL);
  	ptp->tp_next = tab->tp_next;
      }
  
      goto_tabpage_tp(ptp, FALSE, FALSE);
      free_tabpage(tab);
  }
  
  /*
   * Find tab page "n" (first one is 1).  Returns NULL when not found.
   */
      tabpage_T *
  find_tabpage(int n)
  {
      tabpage_T	*tp;
      int		i = 1;
  
      if (n == 0)
  	return curtab;
  
      for (tp = first_tabpage; tp != NULL && i != n; tp = tp->tp_next)
  	++i;
      return tp;
  }
  
  /*
   * Get index of tab page "tp".  First one has index 1.
   * When not found returns number of tab pages plus one.
   */
      int
  tabpage_index(tabpage_T *ftp)
  {
      int		i = 1;
      tabpage_T	*tp;
  
      for (tp = first_tabpage; tp != NULL && tp != ftp; tp = tp->tp_next)
  	++i;
      return i;
  }
  
  /*
   * Prepare for leaving the current tab page.
   * When autocommands change "curtab" we don't leave the tab page and return
   * FAIL.
   * Careful: When OK is returned need to get a new tab page very very soon!
   */
      static int
  leave_tabpage(
      buf_T	*new_curbuf UNUSED,    // what is going to be the new curbuf,
  				       // NULL if unknown
      int		trigger_leave_autocmds UNUSED)
  {
      tabpage_T	*tp = curtab;
  
  #ifdef FEAT_JOB_CHANNEL
      leaving_window(curwin);
  #endif
      reset_VIsual_and_resel();	// stop Visual mode
      if (trigger_leave_autocmds)
      {
  	if (new_curbuf != curbuf)
  	{
  	    apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, FALSE, curbuf);
  	    if (curtab != tp)
  		return FAIL;
  	}
  	apply_autocmds(EVENT_WINLEAVE, NULL, NULL, FALSE, curbuf);
  	if (curtab != tp)
  	    return FAIL;
  	apply_autocmds(EVENT_TABLEAVE, NULL, NULL, FALSE, curbuf);
  	if (curtab != tp)
  	    return FAIL;
      }
  #if defined(FEAT_GUI)
      // Remove the scrollbars.  They may be added back later.
      if (gui.in_use)
  	gui_remove_scrollbars();
  #endif
      tp->tp_curwin = curwin;
      tp->tp_prevwin = prevwin;
      tp->tp_firstwin = firstwin;
      tp->tp_lastwin = lastwin;
      tp->tp_old_Rows = Rows;
      if (tp->tp_old_Columns != -1)
  	tp->tp_old_Columns = Columns;
      firstwin = NULL;
      lastwin = NULL;
      return OK;
  }
  
  /*
   * Start using tab page "tp".
   * Only to be used after leave_tabpage() or freeing the current tab page.
   * Only trigger *Enter autocommands when trigger_enter_autocmds is TRUE.
   * Only trigger *Leave autocommands when trigger_leave_autocmds is TRUE.
   */
      static void
  enter_tabpage(
      tabpage_T	*tp,
      buf_T	*old_curbuf UNUSED,
      int		trigger_enter_autocmds,
      int		trigger_leave_autocmds)
  {
      int		row;
      int		old_off = tp->tp_firstwin->w_winrow;
      win_T	*next_prevwin = tp->tp_prevwin;
      tabpage_T	*last_tab = curtab;
  
      curtab = tp;
      firstwin = tp->tp_firstwin;
      lastwin = tp->tp_lastwin;
      topframe = tp->tp_topframe;
  
      // We would like doing the TabEnter event first, but we don't have a
      // valid current window yet, which may break some commands.
      // This triggers autocommands, thus may make "tp" invalid.
      (void)win_enter_ext(tp->tp_curwin, WEE_CURWIN_INVALID
  		  | (trigger_enter_autocmds ? WEE_TRIGGER_ENTER_AUTOCMDS : 0)
  		  | (trigger_leave_autocmds ? WEE_TRIGGER_LEAVE_AUTOCMDS : 0));
      prevwin = next_prevwin;
  
      last_status(FALSE);		// status line may appear or disappear
      row = win_comp_pos();	// recompute w_winrow for all windows
  #ifdef FEAT_DIFF
      diff_need_scrollbind = TRUE;
  #endif
  
      // The tabpage line may have appeared or disappeared, may need to resize
      // the frames for that.  When the Vim window was resized need to update
      // frame sizes too.  Use the stored value of p_ch, so that it can be
      // different for each tab page.
      if (p_ch != curtab->tp_ch_used)
  	clear_cmdline = TRUE;
      p_ch = curtab->tp_ch_used;
  
      // When cmdheight is changed in a tab page with '<C-w>-', cmdline_row is
      // changed but p_ch and tp_ch_used are not changed. Thus we also need to
      // check cmdline_row.
      if ((row < cmdline_row) && (cmdline_row <= Rows - p_ch))
  	clear_cmdline = TRUE;
  
      if (curtab->tp_old_Rows != Rows || (old_off != firstwin->w_winrow
  #ifdef FEAT_GUI_TABLINE
  			    && !gui_use_tabline()
  #endif
  		))
  	shell_new_rows();
      if (curtab->tp_old_Columns != Columns)
      {
  	if (starting == 0)
  	{
  	    shell_new_columns();	// update window widths
  	    curtab->tp_old_Columns = Columns;
  	}
  	else
  	    curtab->tp_old_Columns = -1;  // update window widths later
      }
  
      lastused_tabpage = last_tab;
  
  #if defined(FEAT_GUI)
      // When 'guioptions' includes 'L' or 'R' may have to remove or add
      // scrollbars.  Have to update them anyway.
      gui_may_update_scrollbars();
  #endif
  
      // Apply autocommands after updating the display, when 'rows' and
      // 'columns' have been set correctly.
      if (trigger_enter_autocmds)
      {
  	apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
  	if (old_curbuf != curbuf)
  	    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
      }
  
      redraw_all_later(NOT_VALID);
  }
  
  /*
   * Go to tab page "n".  For ":tab N" and "Ngt".
   * When "n" is 9999 go to the last tab page.
   */
      void
  goto_tabpage(int n)
  {
      tabpage_T	*tp = NULL;  // shut up compiler
      tabpage_T	*ttp;
      int		i;
  
      if (text_locked())
      {
  	// Not allowed when editing the command line.
  	text_locked_msg();
  	return;
      }
  
      // If there is only one it can't work.
      if (first_tabpage->tp_next == NULL)
      {
  	if (n > 1)
  	    beep_flush();
  	return;
      }
  
      if (n == 0)
      {
  	// No count, go to next tab page, wrap around end.
  	if (curtab->tp_next == NULL)
  	    tp = first_tabpage;
  	else
  	    tp = curtab->tp_next;
      }
      else if (n < 0)
      {
  	// "gT": go to previous tab page, wrap around end.  "N gT" repeats
  	// this N times.
  	ttp = curtab;
  	for (i = n; i < 0; ++i)
  	{
  	    for (tp = first_tabpage; tp->tp_next != ttp && tp->tp_next != NULL;
  		    tp = tp->tp_next)
  		;
  	    ttp = tp;
  	}
      }
      else if (n == 9999)
      {
  	// Go to last tab page.
  	for (tp = first_tabpage; tp->tp_next != NULL; tp = tp->tp_next)
  	    ;
      }
      else
      {
  	// Go to tab page "n".
  	tp = find_tabpage(n);
  	if (tp == NULL)
  	{
  	    beep_flush();
  	    return;
  	}
      }
  
      goto_tabpage_tp(tp, TRUE, TRUE);
  
  #ifdef FEAT_GUI_TABLINE
      if (gui_use_tabline())
  	gui_mch_set_curtab(tabpage_index(curtab));
  #endif
  }
  
  /*
   * Go to tabpage "tp".
   * Only trigger *Enter autocommands when trigger_enter_autocmds is TRUE.
   * Only trigger *Leave autocommands when trigger_leave_autocmds is TRUE.
   * Note: doesn't update the GUI tab.
   */
      void
  goto_tabpage_tp(
      tabpage_T	*tp,
      int		trigger_enter_autocmds,
      int		trigger_leave_autocmds)
  {
      if (trigger_enter_autocmds || trigger_leave_autocmds)
  	CHECK_CMDWIN;
  
      // Don't repeat a message in another tab page.
      set_keep_msg(NULL, 0);
  
      if (tp != curtab && leave_tabpage(tp->tp_curwin->w_buffer,
  					trigger_leave_autocmds) == OK)
      {
  	if (valid_tabpage(tp))
  	    enter_tabpage(tp, curbuf, trigger_enter_autocmds,
  		    trigger_leave_autocmds);
  	else
  	    enter_tabpage(curtab, curbuf, trigger_enter_autocmds,
  		    trigger_leave_autocmds);
      }
  }
  
  /*
   * Go to the last accessed tab page, if there is one.
   * Return OK or FAIL
   */
      int
  goto_tabpage_lastused(void)
  {
      if (valid_tabpage(lastused_tabpage))
      {
  	goto_tabpage_tp(lastused_tabpage, TRUE, TRUE);
  	return OK;
      }
      return FAIL;
  }
  
  /*
   * Enter window "wp" in tab page "tp".
   * Also updates the GUI tab.
   */
      void
  goto_tabpage_win(tabpage_T *tp, win_T *wp)
  {
      goto_tabpage_tp(tp, TRUE, TRUE);
      if (curtab == tp && win_valid(wp))
      {
  	win_enter(wp, TRUE);
  # ifdef FEAT_GUI_TABLINE
  	if (gui_use_tabline())
  	    gui_mch_set_curtab(tabpage_index(curtab));
  # endif
      }
  }
  
  /*
   * Move the current tab page to after tab page "nr".
   */
      void
  tabpage_move(int nr)
  {
      int		n = 1;
      tabpage_T	*tp, *tp_dst;
  
      if (first_tabpage->tp_next == NULL)
  	return;
  
      for (tp = first_tabpage; tp->tp_next != NULL && n < nr; tp = tp->tp_next)
  	++n;
  
      if (tp == curtab || (nr > 0 && tp->tp_next != NULL
  						    && tp->tp_next == curtab))
  	return;
  
      tp_dst = tp;
  
      // Remove the current tab page from the list of tab pages.
      if (curtab == first_tabpage)
  	first_tabpage = curtab->tp_next;
      else
      {
  	FOR_ALL_TABPAGES(tp)
  	    if (tp->tp_next == curtab)
  		break;
  	if (tp == NULL)	// "cannot happen"
  	    return;
  	tp->tp_next = curtab->tp_next;
      }
  
      // Re-insert it at the specified position.
      if (nr <= 0)
      {
  	curtab->tp_next = first_tabpage;
  	first_tabpage = curtab;
      }
      else
      {
  	curtab->tp_next = tp_dst->tp_next;
  	tp_dst->tp_next = curtab;
      }
  
      // Need to redraw the tabline.  Tab page contents doesn't change.
      redraw_tabline = TRUE;
  }
  
  
  /*
   * Go to another window.
   * When jumping to another buffer, stop Visual mode.  Do this before
   * changing windows so we can yank the selection into the '*' register.
   * When jumping to another window on the same buffer, adjust its cursor
   * position to keep the same Visual area.
   */
      void
  win_goto(win_T *wp)
  {
  #ifdef FEAT_CONCEAL
      win_T	*owp = curwin;
  #endif
  
  #ifdef FEAT_PROP_POPUP
      if (ERROR_IF_ANY_POPUP_WINDOW)
  	return;
      if (popup_is_popup(wp))
      {
  	emsg(_(e_not_allowed_to_enter_popup_window));
  	return;
      }
  #endif
      if (text_and_win_locked())
      {
  	beep_flush();
  	text_locked_msg();
  	return;
      }
      if (curbuf_locked())
  	return;
  
      if (wp->w_buffer != curbuf)
  	reset_VIsual_and_resel();
      else if (VIsual_active)
  	wp->w_cursor = curwin->w_cursor;
  
  #ifdef FEAT_GUI
      need_mouse_correct = TRUE;
  #endif
      win_enter(wp, TRUE);
  
  #ifdef FEAT_CONCEAL
      // Conceal cursor line in previous window, unconceal in current window.
      if (win_valid(owp) && owp->w_p_cole > 0 && !msg_scrolled)
  	redrawWinline(owp, owp->w_cursor.lnum);
      if (curwin->w_p_cole > 0 && !msg_scrolled)
  	need_cursor_line_redraw = TRUE;
  #endif
  }
  
  #if defined(FEAT_PERL) || defined(PROTO)
  /*
   * Find window number "winnr" (counting top to bottom).
   */
      win_T *
  win_find_nr(int winnr)
  {
      win_T	*wp;
  
      FOR_ALL_WINDOWS(wp)
  	if (--winnr == 0)
  	    break;
      return wp;
  }
  #endif
  
  #if ((defined(FEAT_PYTHON) || defined(FEAT_PYTHON3))) || defined(PROTO)
  /*
   * Find the tabpage for window "win".
   */
      tabpage_T *
  win_find_tabpage(win_T *win)
  {
      win_T	*wp;
      tabpage_T	*tp;
  
      FOR_ALL_TAB_WINDOWS(tp, wp)
  	    if (wp == win)
  		return tp;
      return NULL;
  }
  #endif
  
  /*
   * Get the above or below neighbor window of the specified window.
   *   up - TRUE for the above neighbor
   *   count - nth neighbor window
   * Returns the specified window if the neighbor is not found.
   */
      win_T *
  win_vert_neighbor(tabpage_T *tp, win_T *wp, int up, long count)
  {
      frame_T	*fr;
      frame_T	*nfr;
      frame_T	*foundfr;
  
  #ifdef FEAT_PROP_POPUP
      if (popup_is_popup(wp))
  	// popups don't have neighbors.
  	return NULL;
  #endif
      foundfr = wp->w_frame;
      while (count--)
      {
  	/*
  	 * First go upwards in the tree of frames until we find a upwards or
  	 * downwards neighbor.
  	 */
  	fr = foundfr;
  	for (;;)
  	{
  	    if (fr == tp->tp_topframe)
  		goto end;
  	    if (up)
  		nfr = fr->fr_prev;
  	    else
  		nfr = fr->fr_next;
  	    if (fr->fr_parent->fr_layout == FR_COL && nfr != NULL)
  		break;
  	    fr = fr->fr_parent;
  	}
  
  	/*
  	 * Now go downwards to find the bottom or top frame in it.
  	 */
  	for (;;)
  	{
  	    if (nfr->fr_layout == FR_LEAF)
  	    {
  		foundfr = nfr;
  		break;
  	    }
  	    fr = nfr->fr_child;
  	    if (nfr->fr_layout == FR_ROW)
  	    {
  		// Find the frame at the cursor row.
  		while (fr->fr_next != NULL
  			&& frame2win(fr)->w_wincol + fr->fr_width
  					 <= wp->w_wincol + wp->w_wcol)
  		    fr = fr->fr_next;
  	    }
  	    if (nfr->fr_layout == FR_COL && up)
  		while (fr->fr_next != NULL)
  		    fr = fr->fr_next;
  	    nfr = fr;
  	}
      }
  end:
      return foundfr != NULL ? foundfr->fr_win : NULL;
  }
  
  /*
   * Move to window above or below "count" times.
   */
      static void
  win_goto_ver(
      int		up,		// TRUE to go to win above
      long	count)
  {
      win_T	*win;
  
  #ifdef FEAT_PROP_POPUP
      if (ERROR_IF_TERM_POPUP_WINDOW)
  	return;
  #endif
      win = win_vert_neighbor(curtab, curwin, up, count);
      if (win != NULL)
  	win_goto(win);
  }
  
  /*
   * Get the left or right neighbor window of the specified window.
   *   left - TRUE for the left neighbor
   *   count - nth neighbor window
   * Returns the specified window if the neighbor is not found.
   */
      win_T *
  win_horz_neighbor(tabpage_T *tp, win_T *wp, int left, long count)
  {
      frame_T	*fr;
      frame_T	*nfr;
      frame_T	*foundfr;
  
  #ifdef FEAT_PROP_POPUP
      if (popup_is_popup(wp))
  	// popups don't have neighbors.
  	return NULL;
  #endif
      foundfr = wp->w_frame;
      while (count--)
      {
  	/*
  	 * First go upwards in the tree of frames until we find a left or
  	 * right neighbor.
  	 */
  	fr = foundfr;
  	for (;;)
  	{
  	    if (fr == tp->tp_topframe)
  		goto end;
  	    if (left)
  		nfr = fr->fr_prev;
  	    else
  		nfr = fr->fr_next;
  	    if (fr->fr_parent->fr_layout == FR_ROW && nfr != NULL)
  		break;
  	    fr = fr->fr_parent;
  	}
  
  	/*
  	 * Now go downwards to find the leftmost or rightmost frame in it.
  	 */
  	for (;;)
  	{
  	    if (nfr->fr_layout == FR_LEAF)
  	    {
  		foundfr = nfr;
  		break;
  	    }
  	    fr = nfr->fr_child;
  	    if (nfr->fr_layout == FR_COL)
  	    {
  		// Find the frame at the cursor row.
  		while (fr->fr_next != NULL
  			&& frame2win(fr)->w_winrow + fr->fr_height
  					 <= wp->w_winrow + wp->w_wrow)
  		    fr = fr->fr_next;
  	    }
  	    if (nfr->fr_layout == FR_ROW && left)
  		while (fr->fr_next != NULL)
  		    fr = fr->fr_next;
  	    nfr = fr;
  	}
      }
  end:
      return foundfr != NULL ? foundfr->fr_win : NULL;
  }
  
  /*
   * Move to left or right window.
   */
      static void
  win_goto_hor(
      int		left,		// TRUE to go to left win
      long	count)
  {
      win_T	*win;
  
  #ifdef FEAT_PROP_POPUP
      if (ERROR_IF_TERM_POPUP_WINDOW)
  	return;
  #endif
      win = win_horz_neighbor(curtab, curwin, left, count);
      if (win != NULL)
  	win_goto(win);
  }
  
  /*
   * Make window "wp" the current window.
   */
      void
  win_enter(win_T *wp, int undo_sync)
  {
      (void)win_enter_ext(wp, (undo_sync ? WEE_UNDO_SYNC : 0)
  		    | WEE_TRIGGER_ENTER_AUTOCMDS | WEE_TRIGGER_LEAVE_AUTOCMDS);
  }
  
  /*
   * Used after making another window the current one: change directory if
   * needed.
   */
      static void
  fix_current_dir(void)
  {
      if (curwin->w_localdir != NULL || curtab->tp_localdir != NULL)
      {
  	char_u	*dirname;
  
  	// Window or tab has a local directory: Save current directory as
  	// global directory (unless that was done already) and change to the
  	// local directory.
  	if (globaldir == NULL)
  	{
  	    char_u	cwd[MAXPATHL];
  
  	    if (mch_dirname(cwd, MAXPATHL) == OK)
  		globaldir = vim_strsave(cwd);
  	}
  	if (curwin->w_localdir != NULL)
  	    dirname = curwin->w_localdir;
  	else
  	    dirname = curtab->tp_localdir;
  
  	if (mch_chdir((char *)dirname) == 0)
  	{
  	    last_chdir_reason = NULL;
  	    shorten_fnames(TRUE);
  	}
      }
      else if (globaldir != NULL)
      {
  	// Window doesn't have a local directory and we are not in the global
  	// directory: Change to the global directory.
  	vim_ignored = mch_chdir((char *)globaldir);
  	VIM_CLEAR(globaldir);
  	last_chdir_reason = NULL;
  	shorten_fnames(TRUE);
      }
  }
  
  /*
   * Make window "wp" the current window.
   * Can be called with "flags" containing WEE_CURWIN_INVALID, which means that
   * curwin has just been closed and isn't valid.
   * Returns TRUE when dont_parse_messages was decremented.
   */
      static int
  win_enter_ext(win_T *wp, int flags)
  {
      int		other_buffer = FALSE;
      int		curwin_invalid = (flags & WEE_CURWIN_INVALID);
      int		did_decrement = FALSE;
  
      if (wp == curwin && !curwin_invalid)	// nothing to do
  	return FALSE;
  
  #ifdef FEAT_JOB_CHANNEL
      if (!curwin_invalid)
  	leaving_window(curwin);
  #endif
  
      if (!curwin_invalid && (flags & WEE_TRIGGER_LEAVE_AUTOCMDS))
      {
  	/*
  	 * Be careful: If autocommands delete the window, return now.
  	 */
  	if (wp->w_buffer != curbuf)
  	{
  	    apply_autocmds(EVENT_BUFLEAVE, NULL, NULL, FALSE, curbuf);
  	    other_buffer = TRUE;
  	    if (!win_valid(wp))
  		return FALSE;
  	}
  	apply_autocmds(EVENT_WINLEAVE, NULL, NULL, FALSE, curbuf);
  	if (!win_valid(wp))
  	    return FALSE;
  #ifdef FEAT_EVAL
  	// autocmds may abort script processing
  	if (aborting())
  	    return FALSE;
  #endif
      }
  
      // sync undo before leaving the current buffer
      if ((flags & WEE_UNDO_SYNC) && curbuf != wp->w_buffer)
  	u_sync(FALSE);
  
      // Might need to scroll the old window before switching, e.g., when the
      // cursor was moved.
      update_topline();
  
      // may have to copy the buffer options when 'cpo' contains 'S'
      if (wp->w_buffer != curbuf)
  	buf_copy_options(wp->w_buffer, BCO_ENTER | BCO_NOHELP);
      if (!curwin_invalid)
      {
  	prevwin = curwin;	// remember for CTRL-W p
  	curwin->w_redr_status = TRUE;
      }
      curwin = wp;
      curbuf = wp->w_buffer;
      check_cursor();
      if (!virtual_active())
  	curwin->w_cursor.coladd = 0;
      changed_line_abv_curs();	// assume cursor position needs updating
  
      // Now it is OK to parse messages again, which may be needed in
      // autocommands.
  #ifdef MESSAGE_QUEUE
      if (flags & WEE_ALLOW_PARSE_MESSAGES)
      {
  	--dont_parse_messages;
  	did_decrement = TRUE;
      }
  #endif
  
      fix_current_dir();
  
  #ifdef FEAT_JOB_CHANNEL
      entering_window(curwin);
  #endif
      // Careful: autocommands may close the window and make "wp" invalid
      if (flags & WEE_TRIGGER_NEW_AUTOCMDS)
  	apply_autocmds(EVENT_WINNEW, NULL, NULL, FALSE, curbuf);
      if (flags & WEE_TRIGGER_ENTER_AUTOCMDS)
      {
  	apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
  	if (other_buffer)
  	    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
      }
  
      maketitle();
      curwin->w_redr_status = TRUE;
  #ifdef FEAT_TERMINAL
      if (bt_terminal(curwin->w_buffer))
  	// terminal is likely in another mode
  	redraw_mode = TRUE;
  #endif
      redraw_tabline = TRUE;
      if (restart_edit)
  	redraw_later(VALID);	// causes status line redraw
  
      // set window height to desired minimal value
      if (curwin->w_height < p_wh && !curwin->w_p_wfh
  #ifdef FEAT_PROP_POPUP
  	    && !popup_is_popup(curwin)
  #endif
  	    )
  	win_setheight((int)p_wh);
      else if (curwin->w_height == 0)
  	win_setheight(1);
  
      // set window width to desired minimal value
      if (curwin->w_width < p_wiw && !curwin->w_p_wfw)
  	win_setwidth((int)p_wiw);
  
      setmouse();			// in case jumped to/from help buffer
  
      // Change directories when the 'acd' option is set.
      DO_AUTOCHDIR;
  
      return did_decrement;
  }
  
  /*
   * Jump to the first open window that contains buffer "buf", if one exists.
   * Returns a pointer to the window found, otherwise NULL.
   */
      win_T *
  buf_jump_open_win(buf_T *buf)
  {
      win_T	*wp = NULL;
  
      if (curwin->w_buffer == buf)
  	wp = curwin;
      else
  	FOR_ALL_WINDOWS(wp)
  	    if (wp->w_buffer == buf)
  		break;
      if (wp != NULL)
  	win_enter(wp, FALSE);
      return wp;
  }
  
  /*
   * Jump to the first open window in any tab page that contains buffer "buf",
   * if one exists. First search in the windows present in the current tab page.
   * Returns a pointer to the window found, otherwise NULL.
   */
      win_T *
  buf_jump_open_tab(buf_T *buf)
  {
      win_T	*wp = buf_jump_open_win(buf);
      tabpage_T	*tp;
  
      if (wp != NULL)
  	return wp;
  
      FOR_ALL_TABPAGES(tp)
  	if (tp != curtab)
  	{
  	    FOR_ALL_WINDOWS_IN_TAB(tp, wp)
  		if (wp->w_buffer == buf)
  		    break;
  	    if (wp != NULL)
  	    {
  		goto_tabpage_win(tp, wp);
  		if (curwin != wp)
  		    wp = NULL;	// something went wrong
  		break;
  	    }
  	}
      return wp;
  }
  
  static int last_win_id = LOWEST_WIN_ID - 1;
  
  /*
   * Allocate a window structure and link it in the window list when "hidden" is
   * FALSE.
   */
      static win_T *
  win_alloc(win_T *after UNUSED, int hidden UNUSED)
  {
      win_T	*new_wp;
  
      /*
       * allocate window structure and linesizes arrays
       */
      new_wp = ALLOC_CLEAR_ONE(win_T);
      if (new_wp == NULL)
  	return NULL;
  
      if (win_alloc_lines(new_wp) == FAIL)
      {
  	vim_free(new_wp);
  	return NULL;
      }
  
      new_wp->w_id = ++last_win_id;
  
  #ifdef FEAT_EVAL
      // init w: variables
      new_wp->w_vars = dict_alloc();
      if (new_wp->w_vars == NULL)
      {
  	win_free_lsize(new_wp);
  	vim_free(new_wp);
  	return NULL;
      }
      init_var_dict(new_wp->w_vars, &new_wp->w_winvar, VAR_SCOPE);
  #endif
  
      // Don't execute autocommands while the window is not properly
      // initialized yet.  gui_create_scrollbar() may trigger a FocusGained
      // event.
      block_autocmds();
  
      /*
       * link the window in the window list
       */
      if (!hidden)
  	win_append(after, new_wp);
      new_wp->w_wincol = 0;
      new_wp->w_width = Columns;
  
      // position the display and the cursor at the top of the file.
      new_wp->w_topline = 1;
  #ifdef FEAT_DIFF
      new_wp->w_topfill = 0;
  #endif
      new_wp->w_botline = 2;
      new_wp->w_cursor.lnum = 1;
      new_wp->w_scbind_pos = 1;
  
      // use global option value for global-local options
      new_wp->w_p_so = -1;
      new_wp->w_p_siso = -1;
  
      // We won't calculate w_fraction until resizing the window
      new_wp->w_fraction = 0;
      new_wp->w_prev_fraction_row = -1;
  
  #ifdef FEAT_GUI
      if (gui.in_use)
      {
  	gui_create_scrollbar(&new_wp->w_scrollbars[SBAR_LEFT],
  		SBAR_LEFT, new_wp);
  	gui_create_scrollbar(&new_wp->w_scrollbars[SBAR_RIGHT],
  		SBAR_RIGHT, new_wp);
      }
  #endif
  #ifdef FEAT_FOLDING
      foldInitWin(new_wp);
  #endif
      unblock_autocmds();
  #ifdef FEAT_SEARCH_EXTRA
      new_wp->w_match_head = NULL;
      new_wp->w_next_match_id = 4;
  #endif
      return new_wp;
  }
  
  /*
   * Remove window 'wp' from the window list and free the structure.
   */
      static void
  win_free(
      win_T	*wp,
      tabpage_T	*tp)		// tab page "win" is in, NULL for current
  {
      int		i;
      buf_T	*buf;
      wininfo_T	*wip;
  
  #ifdef FEAT_FOLDING
      clearFolding(wp);
  #endif
  
      // reduce the reference count to the argument list.
      alist_unlink(wp->w_alist);
  
      // Don't execute autocommands while the window is halfway being deleted.
      // gui_mch_destroy_scrollbar() may trigger a FocusGained event.
      block_autocmds();
  
  #ifdef FEAT_LUA
      lua_window_free(wp);
  #endif
  
  #ifdef FEAT_MZSCHEME
      mzscheme_window_free(wp);
  #endif
  
  #ifdef FEAT_PERL
      perl_win_free(wp);
  #endif
  
  #ifdef FEAT_PYTHON
      python_window_free(wp);
  #endif
  
  #ifdef FEAT_PYTHON3
      python3_window_free(wp);
  #endif
  
  #ifdef FEAT_TCL
      tcl_window_free(wp);
  #endif
  
  #ifdef FEAT_RUBY
      ruby_window_free(wp);
  #endif
  
      clear_winopt(&wp->w_onebuf_opt);
      clear_winopt(&wp->w_allbuf_opt);
  
      vim_free(wp->w_lcs_chars.multispace);
  
  #ifdef FEAT_EVAL
      vars_clear(&wp->w_vars->dv_hashtab);	// free all w: variables
      hash_init(&wp->w_vars->dv_hashtab);
      unref_var_dict(wp->w_vars);
  #endif
  
      {
  	tabpage_T	*ttp;
  
  	if (prevwin == wp)
  	    prevwin = NULL;
  	FOR_ALL_TABPAGES(ttp)
  	    if (ttp->tp_prevwin == wp)
  		ttp->tp_prevwin = NULL;
      }
      win_free_lsize(wp);
  
      for (i = 0; i < wp->w_tagstacklen; ++i)
      {
  	vim_free(wp->w_tagstack[i].tagname);
  	vim_free(wp->w_tagstack[i].user_data);
      }
      vim_free(wp->w_localdir);
      vim_free(wp->w_prevdir);
  
      // Remove the window from the b_wininfo lists, it may happen that the
      // freed memory is re-used for another window.
      FOR_ALL_BUFFERS(buf)
  	FOR_ALL_BUF_WININFO(buf, wip)
  	    if (wip->wi_win == wp)
  	    {
  		wininfo_T	*wip2;
  
  		// If there already is an entry with "wi_win" set to NULL it
  		// must be removed, it would never be used.
  		// Skip "wip" itself, otherwise Coverity complains.
  		for (wip2 = buf->b_wininfo; wip2 != NULL; wip2 = wip2->wi_next)
  		    if (wip2 != wip && wip2->wi_win == NULL)
  		    {
  			if (wip2->wi_next != NULL)
  			    wip2->wi_next->wi_prev = wip2->wi_prev;
  			if (wip2->wi_prev == NULL)
  			    buf->b_wininfo = wip2->wi_next;
  			else
  			    wip2->wi_prev->wi_next = wip2->wi_next;
  			free_wininfo(wip2);
  			break;
  		    }
  
  		wip->wi_win = NULL;
  	    }
  
  #ifdef FEAT_SEARCH_EXTRA
      clear_matches(wp);
  #endif
  
      free_jumplist(wp);
  
  #ifdef FEAT_QUICKFIX
      qf_free_all(wp);
  #endif
  
  #ifdef FEAT_GUI
      if (gui.in_use)
      {
  	gui_mch_destroy_scrollbar(&wp->w_scrollbars[SBAR_LEFT]);
  	gui_mch_destroy_scrollbar(&wp->w_scrollbars[SBAR_RIGHT]);
      }
  #endif // FEAT_GUI
  
  #ifdef FEAT_MENU
      remove_winbar(wp);
  #endif
  #ifdef FEAT_PROP_POPUP
      free_callback(&wp->w_close_cb);
      free_callback(&wp->w_filter_cb);
      for (i = 0; i < 4; ++i)
  	VIM_CLEAR(wp->w_border_highlight[i]);
      vim_free(wp->w_scrollbar_highlight);
      vim_free(wp->w_thumb_highlight);
      vim_free(wp->w_popup_title);
      list_unref(wp->w_popup_mask);
      vim_free(wp->w_popup_mask_cells);
  #endif
  
  #ifdef FEAT_SYN_HL
      vim_free(wp->w_p_cc_cols);
  #endif
  
      if (win_valid_any_tab(wp))
  	win_remove(wp, tp);
      if (autocmd_busy)
      {
  	wp->w_next = au_pending_free_win;
  	au_pending_free_win = wp;
      }
      else
  	vim_free(wp);
  
      unblock_autocmds();
  }
  
  /*
   * Return TRUE if "wp" is not in the list of windows: the autocmd window or a
   * popup window.
   */
      int
  win_unlisted(win_T *wp)
  {
      return wp == aucmd_win || WIN_IS_POPUP(wp);
  }
  
  #if defined(FEAT_PROP_POPUP) || defined(PROTO)
  /*
   * Free a popup window.  This does not take the window out of the window list
   * and assumes there is only one toplevel frame, no split.
   */
      void
  win_free_popup(win_T *win)
  {
      if (bt_popup(win->w_buffer))
  	win_close_buffer(win, DOBUF_WIPE_REUSE, FALSE);
      else
  	close_buffer(win, win->w_buffer, 0, FALSE, FALSE);
  # if defined(FEAT_TIMERS)
      if (win->w_popup_timer != NULL)
  	stop_timer(win->w_popup_timer);
  # endif
      vim_free(win->w_frame);
      win_free(win, NULL);
  }
  #endif
  
  /*
   * Append window "wp" in the window list after window "after".
   */
      static void
  win_append(win_T *after, win_T *wp)
  {
      win_T	*before;
  
      if (after == NULL)	    // after NULL is in front of the first
  	before = firstwin;
      else
  	before = after->w_next;
  
      wp->w_next = before;
      wp->w_prev = after;
      if (after == NULL)
  	firstwin = wp;
      else
  	after->w_next = wp;
      if (before == NULL)
  	lastwin = wp;
      else
  	before->w_prev = wp;
  }
  
  /*
   * Remove a window from the window list.
   */
      void
  win_remove(
      win_T	*wp,
      tabpage_T	*tp)		// tab page "win" is in, NULL for current
  {
      if (wp->w_prev != NULL)
  	wp->w_prev->w_next = wp->w_next;
      else if (tp == NULL)
  	firstwin = curtab->tp_firstwin = wp->w_next;
      else
  	tp->tp_firstwin = wp->w_next;
  
      if (wp->w_next != NULL)
  	wp->w_next->w_prev = wp->w_prev;
      else if (tp == NULL)
  	lastwin = curtab->tp_lastwin = wp->w_prev;
      else
  	tp->tp_lastwin = wp->w_prev;
  }
  
  /*
   * Append frame "frp" in a frame list after frame "after".
   */
      static void
  frame_append(frame_T *after, frame_T *frp)
  {
      frp->fr_next = after->fr_next;
      after->fr_next = frp;
      if (frp->fr_next != NULL)
  	frp->fr_next->fr_prev = frp;
      frp->fr_prev = after;
  }
  
  /*
   * Insert frame "frp" in a frame list before frame "before".
   */
      static void
  frame_insert(frame_T *before, frame_T *frp)
  {
      frp->fr_next = before;
      frp->fr_prev = before->fr_prev;
      before->fr_prev = frp;
      if (frp->fr_prev != NULL)
  	frp->fr_prev->fr_next = frp;
      else
  	frp->fr_parent->fr_child = frp;
  }
  
  /*
   * Remove a frame from a frame list.
   */
      static void
  frame_remove(frame_T *frp)
  {
      if (frp->fr_prev != NULL)
  	frp->fr_prev->fr_next = frp->fr_next;
      else
  	frp->fr_parent->fr_child = frp->fr_next;
      if (frp->fr_next != NULL)
  	frp->fr_next->fr_prev = frp->fr_prev;
  }
  
  /*
   * Allocate w_lines[] for window "wp".
   * Return FAIL for failure, OK for success.
   */
      int
  win_alloc_lines(win_T *wp)
  {
      wp->w_lines_valid = 0;
      wp->w_lines = ALLOC_CLEAR_MULT(wline_T, Rows);
      if (wp->w_lines == NULL)
  	return FAIL;
      return OK;
  }
  
  /*
   * free lsize arrays for a window
   */
      void
  win_free_lsize(win_T *wp)
  {
      // TODO: why would wp be NULL here?
      if (wp != NULL)
  	VIM_CLEAR(wp->w_lines);
  }
  
  /*
   * Called from win_new_shellsize() after Rows changed.
   * This only does the current tab page, others must be done when made active.
   */
      void
  shell_new_rows(void)
  {
      int		h = (int)ROWS_AVAIL;
  
      if (firstwin == NULL)	// not initialized yet
  	return;
      if (h < frame_minheight(topframe, NULL))
  	h = frame_minheight(topframe, NULL);
  
      // First try setting the heights of windows with 'winfixheight'.  If
      // that doesn't result in the right height, forget about that option.
      frame_new_height(topframe, h, FALSE, TRUE);
      if (!frame_check_height(topframe, h))
  	frame_new_height(topframe, h, FALSE, FALSE);
  
      (void)win_comp_pos();		// recompute w_winrow and w_wincol
      compute_cmdrow();
      curtab->tp_ch_used = p_ch;
  
  #if 0
      // Disabled: don't want making the screen smaller make a window larger.
      if (p_ea)
  	win_equal(curwin, FALSE, 'v');
  #endif
  }
  
  /*
   * Called from win_new_shellsize() after Columns changed.
   */
      void
  shell_new_columns(void)
  {
      if (firstwin == NULL)	// not initialized yet
  	return;
  
      // First try setting the widths of windows with 'winfixwidth'.  If that
      // doesn't result in the right width, forget about that option.
      frame_new_width(topframe, (int)Columns, FALSE, TRUE);
      if (!frame_check_width(topframe, Columns))
  	frame_new_width(topframe, (int)Columns, FALSE, FALSE);
  
      (void)win_comp_pos();		// recompute w_winrow and w_wincol
  #if 0
      // Disabled: don't want making the screen smaller make a window larger.
      if (p_ea)
  	win_equal(curwin, FALSE, 'h');
  #endif
  }
  
  #if defined(FEAT_CMDWIN) || defined(PROTO)
  /*
   * Save the size of all windows in "gap".
   */
      void
  win_size_save(garray_T *gap)
  
  {
      win_T	*wp;
  
      ga_init2(gap, sizeof(int), 1);
      if (ga_grow(gap, win_count() * 2 + 1) == OK)
      {
  	// first entry is value of 'lines'
  	((int *)gap->ga_data)[gap->ga_len++] = Rows;
  
  	FOR_ALL_WINDOWS(wp)
  	{
  	    ((int *)gap->ga_data)[gap->ga_len++] =
  					       wp->w_width + wp->w_vsep_width;
  	    ((int *)gap->ga_data)[gap->ga_len++] = wp->w_height;
  	}
      }
  }
  
  /*
   * Restore window sizes, but only if the number of windows is still the same
   * and 'lines' didn't change.
   * Does not free the growarray.
   */
      void
  win_size_restore(garray_T *gap)
  {
      win_T	*wp;
      int		i, j;
  
      if (win_count() * 2 + 1 == gap->ga_len
  	    && ((int *)gap->ga_data)[0] == Rows)
      {
  	// The order matters, because frames contain other frames, but it's
  	// difficult to get right. The easy way out is to do it twice.
  	for (j = 0; j < 2; ++j)
  	{
  	    i = 1;
  	    FOR_ALL_WINDOWS(wp)
  	    {
  		frame_setwidth(wp->w_frame, ((int *)gap->ga_data)[i++]);
  		win_setheight_win(((int *)gap->ga_data)[i++], wp);
  	    }
  	}
  	// recompute the window positions
  	(void)win_comp_pos();
      }
  }
  #endif // FEAT_CMDWIN
  
  /*
   * Update the position for all windows, using the width and height of the
   * frames.
   * Returns the row just after the last window.
   */
      int
  win_comp_pos(void)
  {
      int		row = tabline_height();
      int		col = 0;
  
      frame_comp_pos(topframe, &row, &col);
      return row;
  }
  
  /*
   * Update the position of the windows in frame "topfrp", using the width and
   * height of the frames.
   * "*row" and "*col" are the top-left position of the frame.  They are updated
   * to the bottom-right position plus one.
   */
      static void
  frame_comp_pos(frame_T *topfrp, int *row, int *col)
  {
      win_T	*wp;
      frame_T	*frp;
      int		startcol;
      int		startrow;
      int		h;
  
      wp = topfrp->fr_win;
      if (wp != NULL)
      {
  	if (wp->w_winrow != *row || wp->w_wincol != *col)
  	{
  	    // position changed, redraw
  	    wp->w_winrow = *row;
  	    wp->w_wincol = *col;
  	    redraw_win_later(wp, NOT_VALID);
  	    wp->w_redr_status = TRUE;
  	}
  	// WinBar will not show if the window height is zero
  	h = VISIBLE_HEIGHT(wp) + wp->w_status_height;
  	*row += h > topfrp->fr_height ? topfrp->fr_height : h;
  	*col += wp->w_width + wp->w_vsep_width;
      }
      else
      {
  	startrow = *row;
  	startcol = *col;
  	FOR_ALL_FRAMES(frp, topfrp->fr_child)
  	{
  	    if (topfrp->fr_layout == FR_ROW)
  		*row = startrow;	// all frames are at the same row
  	    else
  		*col = startcol;	// all frames are at the same col
  	    frame_comp_pos(frp, row, col);
  	}
      }
  }
  
  /*
   * Make the current window show at least one line and one column.
   */
      void
  win_ensure_size()
  {
      if (curwin->w_height == 0)
  	win_setheight(1);
      if (curwin->w_width == 0)
  	win_setwidth(1);
  }
  
  /*
   * Set current window height and take care of repositioning other windows to
   * fit around it.
   */
      void
  win_setheight(int height)
  {
      win_setheight_win(height, curwin);
  }
  
  /*
   * Set the window height of window "win" and take care of repositioning other
   * windows to fit around it.
   */
      void
  win_setheight_win(int height, win_T *win)
  {
      int		row;
  
      if (win == curwin)
      {
  	// Always keep current window at least one line high, even when
  	// 'winminheight' is zero.
  	if (height < p_wmh)
  	    height = p_wmh;
  	if (height == 0)
  	    height = 1;
  	height += WINBAR_HEIGHT(curwin);
      }
  
      frame_setheight(win->w_frame, height + win->w_status_height);
  
      // recompute the window positions
      row = win_comp_pos();
  
      /*
       * If there is extra space created between the last window and the command
       * line, clear it.
       */
      if (full_screen && msg_scrolled == 0 && row < cmdline_row)
  	screen_fill(row, cmdline_row, 0, (int)Columns, ' ', ' ', 0);
      cmdline_row = row;
      msg_row = row;
      msg_col = 0;
  
      redraw_all_later(NOT_VALID);
  }
  
  /*
   * Set the height of a frame to "height" and take care that all frames and
   * windows inside it are resized.  Also resize frames on the left and right if
   * the are in the same FR_ROW frame.
   *
   * Strategy:
   * If the frame is part of a FR_COL frame, try fitting the frame in that
   * frame.  If that doesn't work (the FR_COL frame is too small), recursively
   * go to containing frames to resize them and make room.
   * If the frame is part of a FR_ROW frame, all frames must be resized as well.
   * Check for the minimal height of the FR_ROW frame.
   * At the top level we can also use change the command line height.
   */
      static void
  frame_setheight(frame_T *curfrp, int height)
  {
      int		room;		// total number of lines available
      int		take;		// number of lines taken from other windows
      int		room_cmdline;	// lines available from cmdline
      int		run;
      frame_T	*frp;
      int		h;
      int		room_reserved;
  
      // If the height already is the desired value, nothing to do.
      if (curfrp->fr_height == height)
  	return;
  
      if (curfrp->fr_parent == NULL)
      {
  	// topframe: can only change the command line
  	if (height > ROWS_AVAIL)
  	    height = ROWS_AVAIL;
  	if (height > 0)
  	    frame_new_height(curfrp, height, FALSE, FALSE);
      }
      else if (curfrp->fr_parent->fr_layout == FR_ROW)
      {
  	// Row of frames: Also need to resize frames left and right of this
  	// one.  First check for the minimal height of these.
  	h = frame_minheight(curfrp->fr_parent, NULL);
  	if (height < h)
  	    height = h;
  	frame_setheight(curfrp->fr_parent, height);
      }
      else
      {
  	/*
  	 * Column of frames: try to change only frames in this column.
  	 */
  	/*
  	 * Do this twice:
  	 * 1: compute room available, if it's not enough try resizing the
  	 *    containing frame.
  	 * 2: compute the room available and adjust the height to it.
  	 * Try not to reduce the height of a window with 'winfixheight' set.
  	 */
  	for (run = 1; run <= 2; ++run)
  	{
  	    room = 0;
  	    room_reserved = 0;
  	    FOR_ALL_FRAMES(frp, curfrp->fr_parent->fr_child)
  	    {
  		if (frp != curfrp
  			&& frp->fr_win != NULL
  			&& frp->fr_win->w_p_wfh)
  		    room_reserved += frp->fr_height;
  		room += frp->fr_height;
  		if (frp != curfrp)
  		    room -= frame_minheight(frp, NULL);
  	    }
  	    if (curfrp->fr_width != Columns)
  		room_cmdline = 0;
  	    else
  	    {
  		room_cmdline = Rows - p_ch - (lastwin->w_winrow
  						+ VISIBLE_HEIGHT(lastwin)
  						+ lastwin->w_status_height);
  		if (room_cmdline < 0)
  		    room_cmdline = 0;
  	    }
  
  	    if (height <= room + room_cmdline)
  		break;
  	    if (run == 2 || curfrp->fr_width == Columns)
  	    {
  		height = room + room_cmdline;
  		break;
  	    }
  	    frame_setheight(curfrp->fr_parent, height
  		+ frame_minheight(curfrp->fr_parent, NOWIN) - (int)p_wmh - 1);
  	}
  
  	/*
  	 * Compute the number of lines we will take from others frames (can be
  	 * negative!).
  	 */
  	take = height - curfrp->fr_height;
  
  	// If there is not enough room, also reduce the height of a window
  	// with 'winfixheight' set.
  	if (height > room + room_cmdline - room_reserved)
  	    room_reserved = room + room_cmdline - height;
  	// If there is only a 'winfixheight' window and making the
  	// window smaller, need to make the other window taller.
  	if (take < 0 && room - curfrp->fr_height < room_reserved)
  	    room_reserved = 0;
  
  	if (take > 0 && room_cmdline > 0)
  	{
  	    // use lines from cmdline first
  	    if (take < room_cmdline)
  		room_cmdline = take;
  	    take -= room_cmdline;
  	    topframe->fr_height += room_cmdline;
  	}
  
  	/*
  	 * set the current frame to the new height
  	 */
  	frame_new_height(curfrp, height, FALSE, FALSE);
  
  	/*
  	 * First take lines from the frames after the current frame.  If
  	 * that is not enough, takes lines from frames above the current
  	 * frame.
  	 */
  	for (run = 0; run < 2; ++run)
  	{
  	    if (run == 0)
  		frp = curfrp->fr_next;	// 1st run: start with next window
  	    else
  		frp = curfrp->fr_prev;	// 2nd run: start with prev window
  	    while (frp != NULL && take != 0)
  	    {
  		h = frame_minheight(frp, NULL);
  		if (room_reserved > 0
  			&& frp->fr_win != NULL
  			&& frp->fr_win->w_p_wfh)
  		{
  		    if (room_reserved >= frp->fr_height)
  			room_reserved -= frp->fr_height;
  		    else
  		    {
  			if (frp->fr_height - room_reserved > take)
  			    room_reserved = frp->fr_height - take;
  			take -= frp->fr_height - room_reserved;
  			frame_new_height(frp, room_reserved, FALSE, FALSE);
  			room_reserved = 0;
  		    }
  		}
  		else
  		{
  		    if (frp->fr_height - take < h)
  		    {
  			take -= frp->fr_height - h;
  			frame_new_height(frp, h, FALSE, FALSE);
  		    }
  		    else
  		    {
  			frame_new_height(frp, frp->fr_height - take,
  								FALSE, FALSE);
  			take = 0;
  		    }
  		}
  		if (run == 0)
  		    frp = frp->fr_next;
  		else
  		    frp = frp->fr_prev;
  	    }
  	}
      }
  }
  
  /*
   * Set current window width and take care of repositioning other windows to
   * fit around it.
   */
      void
  win_setwidth(int width)
  {
      win_setwidth_win(width, curwin);
  }
  
      void
  win_setwidth_win(int width, win_T *wp)
  {
      // Always keep current window at least one column wide, even when
      // 'winminwidth' is zero.
      if (wp == curwin)
      {
  	if (width < p_wmw)
  	    width = p_wmw;
  	if (width == 0)
  	    width = 1;
      }
      else if (width < 0)
  	width = 0;
  
      frame_setwidth(wp->w_frame, width + wp->w_vsep_width);
  
      // recompute the window positions
      (void)win_comp_pos();
  
      redraw_all_later(NOT_VALID);
  }
  
  /*
   * Set the width of a frame to "width" and take care that all frames and
   * windows inside it are resized.  Also resize frames above and below if the
   * are in the same FR_ROW frame.
   *
   * Strategy is similar to frame_setheight().
   */
      static void
  frame_setwidth(frame_T *curfrp, int width)
  {
      int		room;		// total number of lines available
      int		take;		// number of lines taken from other windows
      int		run;
      frame_T	*frp;
      int		w;
      int		room_reserved;
  
      // If the width already is the desired value, nothing to do.
      if (curfrp->fr_width == width)
  	return;
  
      if (curfrp->fr_parent == NULL)
  	// topframe: can't change width
  	return;
  
      if (curfrp->fr_parent->fr_layout == FR_COL)
      {
  	// Column of frames: Also need to resize frames above and below of
  	// this one.  First check for the minimal width of these.
  	w = frame_minwidth(curfrp->fr_parent, NULL);
  	if (width < w)
  	    width = w;
  	frame_setwidth(curfrp->fr_parent, width);
      }
      else
      {
  	/*
  	 * Row of frames: try to change only frames in this row.
  	 *
  	 * Do this twice:
  	 * 1: compute room available, if it's not enough try resizing the
  	 *    containing frame.
  	 * 2: compute the room available and adjust the width to it.
  	 */
  	for (run = 1; run <= 2; ++run)
  	{
  	    room = 0;
  	    room_reserved = 0;
  	    FOR_ALL_FRAMES(frp, curfrp->fr_parent->fr_child)
  	    {
  		if (frp != curfrp
  			&& frp->fr_win != NULL
  			&& frp->fr_win->w_p_wfw)
  		    room_reserved += frp->fr_width;
  		room += frp->fr_width;
  		if (frp != curfrp)
  		    room -= frame_minwidth(frp, NULL);
  	    }
  
  	    if (width <= room)
  		break;
  	    if (run == 2 || curfrp->fr_height >= ROWS_AVAIL)
  	    {
  		width = room;
  		break;
  	    }
  	    frame_setwidth(curfrp->fr_parent, width
  		 + frame_minwidth(curfrp->fr_parent, NOWIN) - (int)p_wmw - 1);
  	}
  
  	/*
  	 * Compute the number of lines we will take from others frames (can be
  	 * negative!).
  	 */
  	take = width - curfrp->fr_width;
  
  	// If there is not enough room, also reduce the width of a window
  	// with 'winfixwidth' set.
  	if (width > room - room_reserved)
  	    room_reserved = room - width;
  	// If there is only a 'winfixwidth' window and making the
  	// window smaller, need to make the other window narrower.
  	if (take < 0 && room - curfrp->fr_width < room_reserved)
  	    room_reserved = 0;
  
  	/*
  	 * set the current frame to the new width
  	 */
  	frame_new_width(curfrp, width, FALSE, FALSE);
  
  	/*
  	 * First take lines from the frames right of the current frame.  If
  	 * that is not enough, takes lines from frames left of the current
  	 * frame.
  	 */
  	for (run = 0; run < 2; ++run)
  	{
  	    if (run == 0)
  		frp = curfrp->fr_next;	// 1st run: start with next window
  	    else
  		frp = curfrp->fr_prev;	// 2nd run: start with prev window
  	    while (frp != NULL && take != 0)
  	    {
  		w = frame_minwidth(frp, NULL);
  		if (room_reserved > 0
  			&& frp->fr_win != NULL
  			&& frp->fr_win->w_p_wfw)
  		{
  		    if (room_reserved >= frp->fr_width)
  			room_reserved -= frp->fr_width;
  		    else
  		    {
  			if (frp->fr_width - room_reserved > take)
  			    room_reserved = frp->fr_width - take;
  			take -= frp->fr_width - room_reserved;
  			frame_new_width(frp, room_reserved, FALSE, FALSE);
  			room_reserved = 0;
  		    }
  		}
  		else
  		{
  		    if (frp->fr_width - take < w)
  		    {
  			take -= frp->fr_width - w;
  			frame_new_width(frp, w, FALSE, FALSE);
  		    }
  		    else
  		    {
  			frame_new_width(frp, frp->fr_width - take,
  								FALSE, FALSE);
  			take = 0;
  		    }
  		}
  		if (run == 0)
  		    frp = frp->fr_next;
  		else
  		    frp = frp->fr_prev;
  	    }
  	}
      }
  }
  
  /*
   * Check 'winminheight' for a valid value and reduce it if needed.
   */
      void
  win_setminheight(void)
  {
      int		room;
      int		needed;
      int		first = TRUE;
  
      // loop until there is a 'winminheight' that is possible
      while (p_wmh > 0)
      {
  	room = Rows - p_ch;
  	needed = min_rows() - 1;  // 1 was added for the cmdline
  	if (room >= needed)
  	    break;
  	--p_wmh;
  	if (first)
  	{
  	    emsg(_(e_not_enough_room));
  	    first = FALSE;
  	}
      }
  }
  
  /*
   * Check 'winminwidth' for a valid value and reduce it if needed.
   */
      void
  win_setminwidth(void)
  {
      int		room;
      int		needed;
      int		first = TRUE;
  
      // loop until there is a 'winminheight' that is possible
      while (p_wmw > 0)
      {
  	room = Columns;
  	needed = frame_minwidth(topframe, NULL);
  	if (room >= needed)
  	    break;
  	--p_wmw;
  	if (first)
  	{
  	    emsg(_(e_not_enough_room));
  	    first = FALSE;
  	}
      }
  }
  
  /*
   * Status line of dragwin is dragged "offset" lines down (negative is up).
   */
      void
  win_drag_status_line(win_T *dragwin, int offset)
  {
      frame_T	*curfr;
      frame_T	*fr;
      int		room;
      int		row;
      int		up;	// if TRUE, drag status line up, otherwise down
      int		n;
  
      fr = dragwin->w_frame;
      curfr = fr;
      if (fr != topframe)		// more than one window
      {
  	fr = fr->fr_parent;
  	// When the parent frame is not a column of frames, its parent should
  	// be.
  	if (fr->fr_layout != FR_COL)
  	{
  	    curfr = fr;
  	    if (fr != topframe)	// only a row of windows, may drag statusline
  		fr = fr->fr_parent;
  	}
      }
  
      // If this is the last frame in a column, may want to resize the parent
      // frame instead (go two up to skip a row of frames).
      while (curfr != topframe && curfr->fr_next == NULL)
      {
  	if (fr != topframe)
  	    fr = fr->fr_parent;
  	curfr = fr;
  	if (fr != topframe)
  	    fr = fr->fr_parent;
      }
  
      if (offset < 0) // drag up
      {
  	up = TRUE;
  	offset = -offset;
  	// sum up the room of the current frame and above it
  	if (fr == curfr)
  	{
  	    // only one window
  	    room = fr->fr_height - frame_minheight(fr, NULL);
  	}
  	else
  	{
  	    room = 0;
  	    for (fr = fr->fr_child; ; fr = fr->fr_next)
  	    {
  		room += fr->fr_height - frame_minheight(fr, NULL);
  		if (fr == curfr)
  		    break;
  	    }
  	}
  	fr = curfr->fr_next;		// put fr at frame that grows
      }
      else    // drag down
      {
  	up = FALSE;
  	/*
  	 * Only dragging the last status line can reduce p_ch.
  	 */
  	room = Rows - cmdline_row;
  	if (curfr->fr_next == NULL)
  	    room -= 1;
  	else
  	    room -= p_ch;
  	if (room < 0)
  	    room = 0;
  	// sum up the room of frames below of the current one
  	FOR_ALL_FRAMES(fr, curfr->fr_next)
  	    room += fr->fr_height - frame_minheight(fr, NULL);
  	fr = curfr;			// put fr at window that grows
      }
  
      if (room < offset)		// Not enough room
  	offset = room;		// Move as far as we can
      if (offset <= 0)
  	return;
  
      /*
       * Grow frame fr by "offset" lines.
       * Doesn't happen when dragging the last status line up.
       */
      if (fr != NULL)
  	frame_new_height(fr, fr->fr_height + offset, up, FALSE);
  
      if (up)
  	fr = curfr;		// current frame gets smaller
      else
  	fr = curfr->fr_next;	// next frame gets smaller
  
      /*
       * Now make the other frames smaller.
       */
      while (fr != NULL && offset > 0)
      {
  	n = frame_minheight(fr, NULL);
  	if (fr->fr_height - offset <= n)
  	{
  	    offset -= fr->fr_height - n;
  	    frame_new_height(fr, n, !up, FALSE);
  	}
  	else
  	{
  	    frame_new_height(fr, fr->fr_height - offset, !up, FALSE);
  	    break;
  	}
  	if (up)
  	    fr = fr->fr_prev;
  	else
  	    fr = fr->fr_next;
      }
      row = win_comp_pos();
      screen_fill(row, cmdline_row, 0, (int)Columns, ' ', ' ', 0);
      cmdline_row = row;
      p_ch = Rows - cmdline_row;
      if (p_ch < 1)
  	p_ch = 1;
      curtab->tp_ch_used = p_ch;
      redraw_all_later(SOME_VALID);
      showmode();
  }
  
  /*
   * Separator line of dragwin is dragged "offset" lines right (negative is left).
   */
      void
  win_drag_vsep_line(win_T *dragwin, int offset)
  {
      frame_T	*curfr;
      frame_T	*fr;
      int		room;
      int		left;	// if TRUE, drag separator line left, otherwise right
      int		n;
  
      fr = dragwin->w_frame;
      if (fr == topframe)		// only one window (cannot happen?)
  	return;
      curfr = fr;
      fr = fr->fr_parent;
      // When the parent frame is not a row of frames, its parent should be.
      if (fr->fr_layout != FR_ROW)
      {
  	if (fr == topframe)	// only a column of windows (cannot happen?)
  	    return;
  	curfr = fr;
  	fr = fr->fr_parent;
      }
  
      // If this is the last frame in a row, may want to resize a parent
      // frame instead.
      while (curfr->fr_next == NULL)
      {
  	if (fr == topframe)
  	    break;
  	curfr = fr;
  	fr = fr->fr_parent;
  	if (fr != topframe)
  	{
  	    curfr = fr;
  	    fr = fr->fr_parent;
  	}
      }
  
      if (offset < 0) // drag left
      {
  	left = TRUE;
  	offset = -offset;
  	// sum up the room of the current frame and left of it
  	room = 0;
  	for (fr = fr->fr_child; ; fr = fr->fr_next)
  	{
  	    room += fr->fr_width - frame_minwidth(fr, NULL);
  	    if (fr == curfr)
  		break;
  	}
  	fr = curfr->fr_next;		// put fr at frame that grows
      }
      else    // drag right
      {
  	left = FALSE;
  	// sum up the room of frames right of the current one
  	room = 0;
  	FOR_ALL_FRAMES(fr, curfr->fr_next)
  	    room += fr->fr_width - frame_minwidth(fr, NULL);
  	fr = curfr;			// put fr at window that grows
      }
  
      if (room < offset)		// Not enough room
  	offset = room;		// Move as far as we can
      if (offset <= 0)		// No room at all, quit.
  	return;
      if (fr == NULL)
  	// This can happen when calling win_move_separator() on the rightmost
  	// window.  Just don't do anything.
  	return;			
  
      // grow frame fr by offset lines
      frame_new_width(fr, fr->fr_width + offset, left, FALSE);
  
      // shrink other frames: current and at the left or at the right
      if (left)
  	fr = curfr;		// current frame gets smaller
      else
  	fr = curfr->fr_next;	// next frame gets smaller
  
      while (fr != NULL && offset > 0)
      {
  	n = frame_minwidth(fr, NULL);
  	if (fr->fr_width - offset <= n)
  	{
  	    offset -= fr->fr_width - n;
  	    frame_new_width(fr, n, !left, FALSE);
  	}
  	else
  	{
  	    frame_new_width(fr, fr->fr_width - offset, !left, FALSE);
  	    break;
  	}
  	if (left)
  	    fr = fr->fr_prev;
  	else
  	    fr = fr->fr_next;
      }
      (void)win_comp_pos();
      redraw_all_later(NOT_VALID);
  }
  
  #define FRACTION_MULT	16384L
  
  /*
   * Set wp->w_fraction for the current w_wrow and w_height.
   * Has no effect when the window is less than two lines.
   */
      void
  set_fraction(win_T *wp)
  {
      if (wp->w_height > 1)
  	// When cursor is in the first line the percentage is computed as if
  	// it's halfway that line.  Thus with two lines it is 25%, with three
  	// lines 17%, etc.  Similarly for the last line: 75%, 83%, etc.
  	wp->w_fraction = ((long)wp->w_wrow * FRACTION_MULT
  				     + FRACTION_MULT / 2) / (long)wp->w_height;
  }
  
  /*
   * Set the height of a window.
   * "height" excludes any window toolbar.
   * This takes care of the things inside the window, not what happens to the
   * window position, the frame or to other windows.
   */
      void
  win_new_height(win_T *wp, int height)
  {
      int		prev_height = wp->w_height;
  
      // Don't want a negative height.  Happens when splitting a tiny window.
      // Will equalize heights soon to fix it.
      if (height < 0)
  	height = 0;
      if (wp->w_height == height)
  	return;	    // nothing to do
  
      if (wp->w_height > 0)
      {
  	if (wp == curwin)
  	    // w_wrow needs to be valid. When setting 'laststatus' this may
  	    // call win_new_height() recursively.
  	    validate_cursor();
  	if (wp->w_height != prev_height)
  	    return;  // Recursive call already changed the size, bail out here
  		     //	to avoid the following to mess things up.
  	if (wp->w_wrow != wp->w_prev_fraction_row)
  	    set_fraction(wp);
      }
  
      wp->w_height = height;
      wp->w_skipcol = 0;
  
      // There is no point in adjusting the scroll position when exiting.  Some
      // values might be invalid.
      if (!exiting)
  	scroll_to_fraction(wp, prev_height);
  }
  
      void
  scroll_to_fraction(win_T *wp, int prev_height)
  {
      linenr_T	lnum;
      int		sline, line_size;
      int		height = wp->w_height;
  
      // Don't change w_topline in any of these cases:
      // - window height is 0
      // - 'scrollbind' is set and this isn't the current window
      // - window height is sufficient to display the whole buffer and first line
      //   is visible.
      if (height > 0
          && (!wp->w_p_scb || wp == curwin)
          && (height < wp->w_buffer->b_ml.ml_line_count || wp->w_topline > 1))
      {
  	/*
  	 * Find a value for w_topline that shows the cursor at the same
  	 * relative position in the window as before (more or less).
  	 */
  	lnum = wp->w_cursor.lnum;
  	if (lnum < 1)		// can happen when starting up
  	    lnum = 1;
  	wp->w_wrow = ((long)wp->w_fraction * (long)height - 1L)
  							       / FRACTION_MULT;
  	line_size = plines_win_col(wp, lnum, (long)(wp->w_cursor.col)) - 1;
  	sline = wp->w_wrow - line_size;
  
  	if (sline >= 0)
  	{
  	    // Make sure the whole cursor line is visible, if possible.
  	    int rows = plines_win(wp, lnum, FALSE);
  
  	    if (sline > wp->w_height - rows)
  	    {
  		sline = wp->w_height - rows;
  		wp->w_wrow -= rows - line_size;
  	    }
  	}
  
  	if (sline < 0)
  	{
  	    /*
  	     * Cursor line would go off top of screen if w_wrow was this high.
  	     * Make cursor line the first line in the window.  If not enough
  	     * room use w_skipcol;
  	     */
  	    wp->w_wrow = line_size;
  	    if (wp->w_wrow >= wp->w_height
  				       && (wp->w_width - win_col_off(wp)) > 0)
  	    {
  		wp->w_skipcol += wp->w_width - win_col_off(wp);
  		--wp->w_wrow;
  		while (wp->w_wrow >= wp->w_height)
  		{
  		    wp->w_skipcol += wp->w_width - win_col_off(wp)
  							   + win_col_off2(wp);
  		    --wp->w_wrow;
  		}
  	    }
  	}
  	else if (sline > 0)
  	{
  	    while (sline > 0 && lnum > 1)
  	    {
  #ifdef FEAT_FOLDING
  		hasFoldingWin(wp, lnum, &lnum, NULL, TRUE, NULL);
  		if (lnum == 1)
  		{
  		    // first line in buffer is folded
  		    line_size = 1;
  		    --sline;
  		    break;
  		}
  #endif
  		--lnum;
  #ifdef FEAT_DIFF
  		if (lnum == wp->w_topline)
  		    line_size = plines_win_nofill(wp, lnum, TRUE)
  							      + wp->w_topfill;
  		else
  #endif
  		    line_size = plines_win(wp, lnum, TRUE);
  		sline -= line_size;
  	    }
  
  	    if (sline < 0)
  	    {
  		/*
  		 * Line we want at top would go off top of screen.  Use next
  		 * line instead.
  		 */
  #ifdef FEAT_FOLDING
  		hasFoldingWin(wp, lnum, NULL, &lnum, TRUE, NULL);
  #endif
  		lnum++;
  		wp->w_wrow -= line_size + sline;
  	    }
  	    else if (sline > 0)
  	    {
  		// First line of file reached, use that as topline.
  		lnum = 1;
  		wp->w_wrow -= sline;
  	    }
  	}
  	set_topline(wp, lnum);
      }
  
      if (wp == curwin)
      {
  	if (get_scrolloff_value())
  	    update_topline();
  	curs_columns(FALSE);	// validate w_wrow
      }
      if (prev_height > 0)
  	wp->w_prev_fraction_row = wp->w_wrow;
  
      win_comp_scroll(wp);
      redraw_win_later(wp, SOME_VALID);
      wp->w_redr_status = TRUE;
      invalidate_botline_win(wp);
  }
  
  /*
   * Set the width of a window.
   */
      void
  win_new_width(win_T *wp, int width)
  {
      wp->w_width = width;
      wp->w_lines_valid = 0;
      changed_line_abv_curs_win(wp);
      invalidate_botline_win(wp);
      if (wp == curwin)
      {
  	update_topline();
  	curs_columns(TRUE);	// validate w_wrow
      }
      redraw_win_later(wp, NOT_VALID);
      wp->w_redr_status = TRUE;
  }
  
      void
  win_comp_scroll(win_T *wp)
  {
  #if defined(FEAT_EVAL)
      int old_w_p_scr = wp->w_p_scr;
  #endif
  
      wp->w_p_scr = ((unsigned)wp->w_height >> 1);
      if (wp->w_p_scr == 0)
  	wp->w_p_scr = 1;
  #if defined(FEAT_EVAL)
      if (wp->w_p_scr != old_w_p_scr)
      {
  	// Used by "verbose set scroll".
  	wp->w_p_script_ctx[WV_SCROLL].sc_sid = SID_WINLAYOUT;
  	wp->w_p_script_ctx[WV_SCROLL].sc_lnum = 0;
      }
  #endif
  }
  
  /*
   * command_height: called whenever p_ch has been changed
   */
      void
  command_height(void)
  {
      int		h;
      frame_T	*frp;
      int		old_p_ch = curtab->tp_ch_used;
  
      // Use the value of p_ch that we remembered.  This is needed for when the
      // GUI starts up, we can't be sure in what order things happen.  And when
      // p_ch was changed in another tab page.
      curtab->tp_ch_used = p_ch;
  
      // Find bottom frame with width of screen.
      frp = lastwin->w_frame;
      while (frp->fr_width != Columns && frp->fr_parent != NULL)
  	frp = frp->fr_parent;
  
      // Avoid changing the height of a window with 'winfixheight' set.
      while (frp->fr_prev != NULL && frp->fr_layout == FR_LEAF
  						      && frp->fr_win->w_p_wfh)
  	frp = frp->fr_prev;
  
      if (starting != NO_SCREEN)
      {
  	cmdline_row = Rows - p_ch;
  
  	if (p_ch > old_p_ch)		    // p_ch got bigger
  	{
  	    while (p_ch > old_p_ch)
  	    {
  		if (frp == NULL)
  		{
  		    emsg(_(e_not_enough_room));
  		    p_ch = old_p_ch;
  		    curtab->tp_ch_used = p_ch;
  		    cmdline_row = Rows - p_ch;
  		    break;
  		}
  		h = frp->fr_height - frame_minheight(frp, NULL);
  		if (h > p_ch - old_p_ch)
  		    h = p_ch - old_p_ch;
  		old_p_ch += h;
  		frame_add_height(frp, -h);
  		frp = frp->fr_prev;
  	    }
  
  	    // Recompute window positions.
  	    (void)win_comp_pos();
  
  	    // clear the lines added to cmdline
  	    if (full_screen)
  		screen_fill(cmdline_row, (int)Rows, 0,
  						   (int)Columns, ' ', ' ', 0);
  	    msg_row = cmdline_row;
  	    redraw_cmdline = TRUE;
  	    return;
  	}
  
  	if (msg_row < cmdline_row)
  	    msg_row = cmdline_row;
  	redraw_cmdline = TRUE;
      }
      frame_add_height(frp, (int)(old_p_ch - p_ch));
  
      // Recompute window positions.
      if (frp != lastwin->w_frame)
  	(void)win_comp_pos();
  }
  
  /*
   * Resize frame "frp" to be "n" lines higher (negative for less high).
   * Also resize the frames it is contained in.
   */
      static void
  frame_add_height(frame_T *frp, int n)
  {
      frame_new_height(frp, frp->fr_height + n, FALSE, FALSE);
      for (;;)
      {
  	frp = frp->fr_parent;
  	if (frp == NULL)
  	    break;
  	frp->fr_height += n;
      }
  }
  
  /*
   * Add or remove a status line for the bottom window(s), according to the
   * value of 'laststatus'.
   */
      void
  last_status(
      int		morewin)	// pretend there are two or more windows
  {
      // Don't make a difference between horizontal or vertical split.
      last_status_rec(topframe, (p_ls == 2
  			  || (p_ls == 1 && (morewin || !ONE_WINDOW))));
  }
  
      static void
  last_status_rec(frame_T *fr, int statusline)
  {
      frame_T	*fp;
      win_T	*wp;
  
      if (fr->fr_layout == FR_LEAF)
      {
  	wp = fr->fr_win;
  	if (wp->w_status_height != 0 && !statusline)
  	{
  	    // remove status line
  	    win_new_height(wp, wp->w_height + 1);
  	    wp->w_status_height = 0;
  	    comp_col();
  	}
  	else if (wp->w_status_height == 0 && statusline)
  	{
  	    // Find a frame to take a line from.
  	    fp = fr;
  	    while (fp->fr_height <= frame_minheight(fp, NULL))
  	    {
  		if (fp == topframe)
  		{
  		    emsg(_(e_not_enough_room));
  		    return;
  		}
  		// In a column of frames: go to frame above.  If already at
  		// the top or in a row of frames: go to parent.
  		if (fp->fr_parent->fr_layout == FR_COL && fp->fr_prev != NULL)
  		    fp = fp->fr_prev;
  		else
  		    fp = fp->fr_parent;
  	    }
  	    wp->w_status_height = 1;
  	    if (fp != fr)
  	    {
  		frame_new_height(fp, fp->fr_height - 1, FALSE, FALSE);
  		frame_fix_height(wp);
  		(void)win_comp_pos();
  	    }
  	    else
  		win_new_height(wp, wp->w_height - 1);
  	    comp_col();
  	    redraw_all_later(SOME_VALID);
  	}
      }
      else if (fr->fr_layout == FR_ROW)
      {
  	// vertically split windows, set status line for each one
  	FOR_ALL_FRAMES(fp, fr->fr_child)
  	    last_status_rec(fp, statusline);
      }
      else
      {
  	// horizontally split window, set status line for last one
  	for (fp = fr->fr_child; fp->fr_next != NULL; fp = fp->fr_next)
  	    ;
  	last_status_rec(fp, statusline);
      }
  }
  
  /*
   * Return the number of lines used by the tab page line.
   */
      int
  tabline_height(void)
  {
  #ifdef FEAT_GUI_TABLINE
      // When the GUI has the tabline then this always returns zero.
      if (gui_use_tabline())
  	return 0;
  #endif
      switch (p_stal)
      {
  	case 0: return 0;
  	case 1: return (first_tabpage->tp_next == NULL) ? 0 : 1;
      }
      return 1;
  }
  
  /*
   * Return the minimal number of rows that is needed on the screen to display
   * the current number of windows.
   */
      int
  min_rows(void)
  {
      int		total;
      tabpage_T	*tp;
      int		n;
  
      if (firstwin == NULL)	// not initialized yet
  	return MIN_LINES;
  
      total = 0;
      FOR_ALL_TABPAGES(tp)
      {
  	n = frame_minheight(tp->tp_topframe, NULL);
  	if (total < n)
  	    total = n;
      }
      total += tabline_height();
      total += 1;		// count the room for the command line
      return total;
  }
  
  /*
   * Return TRUE if there is only one window and only one tab page, not
   * counting a help or preview window, unless it is the current window.
   * Does not count unlisted windows.
   */
      int
  only_one_window(void)
  {
      int		count = 0;
      win_T	*wp;
  
  #if defined(FEAT_PROP_POPUP)
      // If the current window is a popup then there always is another window.
      if (popup_is_popup(curwin))
  	return FALSE;
  #endif
  
      // If there is another tab page there always is another window.
      if (first_tabpage->tp_next != NULL)
  	return FALSE;
  
      FOR_ALL_WINDOWS(wp)
  	if (wp->w_buffer != NULL
  		&& (!((bt_help(wp->w_buffer) && !bt_help(curbuf))
  # ifdef FEAT_QUICKFIX
  		    || wp->w_p_pvw
  # endif
  	     ) || wp == curwin) && wp != aucmd_win)
  	    ++count;
      return (count <= 1);
  }
  
  /*
   * Correct the cursor line number in other windows.  Used after changing the
   * current buffer, and before applying autocommands.
   * When "do_curwin" is TRUE, also check current window.
   */
      void
  check_lnums(int do_curwin)
  {
      win_T	*wp;
      tabpage_T	*tp;
  
      FOR_ALL_TAB_WINDOWS(tp, wp)
  	if ((do_curwin || wp != curwin) && wp->w_buffer == curbuf)
  	{
  	    // save the original cursor position and topline
  	    wp->w_save_cursor.w_cursor_save = wp->w_cursor;
  	    wp->w_save_cursor.w_topline_save = wp->w_topline;
  
  	    if (wp->w_cursor.lnum > curbuf->b_ml.ml_line_count)
  		wp->w_cursor.lnum = curbuf->b_ml.ml_line_count;
  	    if (wp->w_topline > curbuf->b_ml.ml_line_count)
  		wp->w_topline = curbuf->b_ml.ml_line_count;
  
  	    // save the corrected cursor position and topline
  	    wp->w_save_cursor.w_cursor_corr = wp->w_cursor;
  	    wp->w_save_cursor.w_topline_corr = wp->w_topline;
  	}
  }
  
  /*
   * Reset cursor and topline to its stored values from check_lnums().
   * check_lnums() must have been called first!
   */
      void
  reset_lnums()
  {
      win_T	*wp;
      tabpage_T	*tp;
  
      FOR_ALL_TAB_WINDOWS(tp, wp)
  	if (wp->w_buffer == curbuf)
  	{
  	    // Restore the value if the autocommand didn't change it.
  	    if (EQUAL_POS(wp->w_save_cursor.w_cursor_corr, wp->w_cursor))
  		wp->w_cursor = wp->w_save_cursor.w_cursor_save;
  	    if (wp->w_save_cursor.w_topline_corr == wp->w_topline)
  		wp->w_topline = wp->w_save_cursor.w_topline_save;
  	}
  }
  
  /*
   * A snapshot of the window sizes, to restore them after closing the help
   * window.
   * Only these fields are used:
   * fr_layout
   * fr_width
   * fr_height
   * fr_next
   * fr_child
   * fr_win (only valid for the old curwin, NULL otherwise)
   */
  
  /*
   * Create a snapshot of the current frame sizes.
   */
      void
  make_snapshot(int idx)
  {
      clear_snapshot(curtab, idx);
      make_snapshot_rec(topframe, &curtab->tp_snapshot[idx]);
  }
  
      static void
  make_snapshot_rec(frame_T *fr, frame_T **frp)
  {
      *frp = ALLOC_CLEAR_ONE(frame_T);
      if (*frp == NULL)
  	return;
      (*frp)->fr_layout = fr->fr_layout;
      (*frp)->fr_width = fr->fr_width;
      (*frp)->fr_height = fr->fr_height;
      if (fr->fr_next != NULL)
  	make_snapshot_rec(fr->fr_next, &((*frp)->fr_next));
      if (fr->fr_child != NULL)
  	make_snapshot_rec(fr->fr_child, &((*frp)->fr_child));
      if (fr->fr_layout == FR_LEAF && fr->fr_win == curwin)
  	(*frp)->fr_win = curwin;
  }
  
  /*
   * Remove any existing snapshot.
   */
      static void
  clear_snapshot(tabpage_T *tp, int idx)
  {
      clear_snapshot_rec(tp->tp_snapshot[idx]);
      tp->tp_snapshot[idx] = NULL;
  }
  
      static void
  clear_snapshot_rec(frame_T *fr)
  {
      if (fr != NULL)
      {
  	clear_snapshot_rec(fr->fr_next);
  	clear_snapshot_rec(fr->fr_child);
  	vim_free(fr);
      }
  }
  
  /*
   * Restore a previously created snapshot, if there is any.
   * This is only done if the screen size didn't change and the window layout is
   * still the same.
   */
      void
  restore_snapshot(
      int		idx,
      int		close_curwin)	    // closing current window
  {
      win_T	*wp;
  
      if (curtab->tp_snapshot[idx] != NULL
  	    && curtab->tp_snapshot[idx]->fr_width == topframe->fr_width
  	    && curtab->tp_snapshot[idx]->fr_height == topframe->fr_height
  	    && check_snapshot_rec(curtab->tp_snapshot[idx], topframe) == OK)
      {
  	wp = restore_snapshot_rec(curtab->tp_snapshot[idx], topframe);
  	win_comp_pos();
  	if (wp != NULL && close_curwin)
  	    win_goto(wp);
  	redraw_all_later(NOT_VALID);
      }
      clear_snapshot(curtab, idx);
  }
  
  /*
   * Check if frames "sn" and "fr" have the same layout, same following frames
   * and same children.  And the window pointer is valid.
   */
      static int
  check_snapshot_rec(frame_T *sn, frame_T *fr)
  {
      if (sn->fr_layout != fr->fr_layout
  	    || (sn->fr_next == NULL) != (fr->fr_next == NULL)
  	    || (sn->fr_child == NULL) != (fr->fr_child == NULL)
  	    || (sn->fr_next != NULL
  		&& check_snapshot_rec(sn->fr_next, fr->fr_next) == FAIL)
  	    || (sn->fr_child != NULL
  		&& check_snapshot_rec(sn->fr_child, fr->fr_child) == FAIL)
  	    || (sn->fr_win != NULL && !win_valid(sn->fr_win)))
  	return FAIL;
      return OK;
  }
  
  /*
   * Copy the size of snapshot frame "sn" to frame "fr".  Do the same for all
   * following frames and children.
   * Returns a pointer to the old current window, or NULL.
   */
      static win_T *
  restore_snapshot_rec(frame_T *sn, frame_T *fr)
  {
      win_T	*wp = NULL;
      win_T	*wp2;
  
      fr->fr_height = sn->fr_height;
      fr->fr_width = sn->fr_width;
      if (fr->fr_layout == FR_LEAF)
      {
  	frame_new_height(fr, fr->fr_height, FALSE, FALSE);
  	frame_new_width(fr, fr->fr_width, FALSE, FALSE);
  	wp = sn->fr_win;
      }
      if (sn->fr_next != NULL)
      {
  	wp2 = restore_snapshot_rec(sn->fr_next, fr->fr_next);
  	if (wp2 != NULL)
  	    wp = wp2;
      }
      if (sn->fr_child != NULL)
      {
  	wp2 = restore_snapshot_rec(sn->fr_child, fr->fr_child);
  	if (wp2 != NULL)
  	    wp = wp2;
      }
      return wp;
  }
  
  #if defined(FEAT_GUI) || defined(PROTO)
  /*
   * Return TRUE if there is any vertically split window.
   */
      int
  win_hasvertsplit(void)
  {
      frame_T	*fr;
  
      if (topframe->fr_layout == FR_ROW)
  	return TRUE;
  
      if (topframe->fr_layout == FR_COL)
  	FOR_ALL_FRAMES(fr, topframe->fr_child)
  	    if (fr->fr_layout == FR_ROW)
  		return TRUE;
  
      return FALSE;
  }
  #endif
  
  #if defined(FEAT_PYTHON) || defined(FEAT_PYTHON3) || defined(PROTO)
      int
  get_win_number(win_T *wp, win_T *first_win)
  {
      int		i = 1;
      win_T	*w;
  
      for (w = first_win; w != NULL && w != wp; w = W_NEXT(w))
  	++i;
  
      if (w == NULL)
  	return 0;
      else
  	return i;
  }
  
      int
  get_tab_number(tabpage_T *tp UNUSED)
  {
      int		i = 1;
      tabpage_T	*t;
  
      for (t = first_tabpage; t != NULL && t != tp; t = t->tp_next)
  	++i;
  
      if (t == NULL)
  	return 0;
      else
  	return i;
  }
  #endif
  
  /*
   * Return TRUE if "topfrp" and its children are at the right height.
   */
      static int
  frame_check_height(frame_T *topfrp, int height)
  {
      frame_T *frp;
  
      if (topfrp->fr_height != height)
  	return FALSE;
  
      if (topfrp->fr_layout == FR_ROW)
  	FOR_ALL_FRAMES(frp, topfrp->fr_child)
  	    if (frp->fr_height != height)
  		return FALSE;
  
      return TRUE;
  }
  
  /*
   * Return TRUE if "topfrp" and its children are at the right width.
   */
      static int
  frame_check_width(frame_T *topfrp, int width)
  {
      frame_T *frp;
  
      if (topfrp->fr_width != width)
  	return FALSE;
  
      if (topfrp->fr_layout == FR_COL)
  	FOR_ALL_FRAMES(frp, topfrp->fr_child)
  	    if (frp->fr_width != width)
  		return FALSE;
  
      return TRUE;
  }
  
  #if defined(FEAT_SYN_HL) || defined(PROTO)
  /*
   * Simple int comparison function for use with qsort()
   */
      static int
  int_cmp(const void *a, const void *b)
  {
      return *(const int *)a - *(const int *)b;
  }
  
  /*
   * Handle setting 'colorcolumn' or 'textwidth' in window "wp".
   * Returns error message, NULL if it's OK.
   */
      char *
  check_colorcolumn(win_T *wp)
  {
      char_u	*s;
      int		col;
      int		count = 0;
      int		color_cols[256];
      int		i;
      int		j = 0;
  
      if (wp->w_buffer == NULL)
  	return NULL;  // buffer was closed
  
      for (s = wp->w_p_cc; *s != NUL && count < 255;)
      {
  	if (*s == '-' || *s == '+')
  	{
  	    // -N and +N: add to 'textwidth'
  	    col = (*s == '-') ? -1 : 1;
  	    ++s;
  	    if (!VIM_ISDIGIT(*s))
  		return e_invalid_argument;
  	    col = col * getdigits(&s);
  	    if (wp->w_buffer->b_p_tw == 0)
  		goto skip;  // 'textwidth' not set, skip this item
  	    col += wp->w_buffer->b_p_tw;
  	    if (col < 0)
  		goto skip;
  	}
  	else if (VIM_ISDIGIT(*s))
  	    col = getdigits(&s);
  	else
  	    return e_invalid_argument;
  	color_cols[count++] = col - 1;  // 1-based to 0-based
  skip:
  	if (*s == NUL)
  	    break;
  	if (*s != ',')
  	    return e_invalid_argument;
  	if (*++s == NUL)
  	    return e_invalid_argument;  // illegal trailing comma as in "set cc=80,"
      }
  
      vim_free(wp->w_p_cc_cols);
      if (count == 0)
  	wp->w_p_cc_cols = NULL;
      else
      {
  	wp->w_p_cc_cols = ALLOC_MULT(int, count + 1);
  	if (wp->w_p_cc_cols != NULL)
  	{
  	    // sort the columns for faster usage on screen redraw inside
  	    // win_line()
  	    qsort(color_cols, count, sizeof(int), int_cmp);
  
  	    for (i = 0; i < count; ++i)
  		// skip duplicates
  		if (j == 0 || wp->w_p_cc_cols[j - 1] != color_cols[i])
  		    wp->w_p_cc_cols[j++] = color_cols[i];
  	    wp->w_p_cc_cols[j] = -1;  // end marker
  	}
      }
  
      return NULL;  // no error
  }
  #endif
  