can't omit WINDOW in set-window-vscroll

[Kalle Olavi Niemitalo]

In GNU Emacs 21.1.1 (i386-debian-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2001-10-29 on Astalo, modified by Debian
configured using `configure  i386-debian-linux-gnu --prefix=/usr 
--sharedstatedir=/var/lib --libexecdir=/usr/lib --localstatedir=/var/lib 
--infodir=/usr/share/info --mandir=/usr/share/man --with-pop=yes --with-x=yes 
--with-x-toolkit=athena'
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: fi_FI
  locale-coding-system: iso-latin-1
  default-enable-multibyte-characters: t

The documentation string of set-window-vscroll says:
> Set amount by which WINDOW should be scrolled vertically to VSCROLL.
> WINDOW nil or omitted means use the selected window.  VSCROLL is a
> non-negative multiple of the canonical character height of WINDOW.

However, the WINDOW argument cannot be omitted, because the
required VSCROLL argument follows it.

Recent input:
<prior> M-: <up> C-e <left> <backspace> 0 <return> 
C-s C-s C-s <backspace> <backspace> <backspace> C-a 
C-s C-s <backspace> C-s <backspace> C-s C-a C-s C-s 
C-s C-a <prior> <prior> <next> C-s D E F U N C-a <down> 
<down> <down> <down> <down> <down> <down> <down> <down> 
<down> <up> C-s C-s C-a <down> <down> <down> <down> 
<down> <down> <mouse-movement> C-x 1 C-s C-s <backspace> 
<up> <up> C-s C-s C-a <down> <down> <up> <up> M-f M-f 
M-f C-h f <return> C-a <next> <prior> M-x r e p o r 
t SPC e m a c s SPC b u f <backspace> g <return>

Recent messages:
Mark saved where search started [8 times]
Type C-x 1 to remove help window.  C-M-v to scroll the help.
nil [10 times]
list: Quit
nil
Mark saved where search started
nil
Mark saved where search started [5 times]
Type C-x 1 to remove help window.  C-M-v to scroll the help.
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