附录 E 中的信件格式示例有些奇怪电子书。
在第 253 页上，如果使用标题，则 \voffset 应该增加两行文本。这解释了为什么在附录 E 中这样做：
...
\voffset=24pt
\advance\vsize by-\voffset
...
\nopagenumbers
\headline={\ifnum\pageno>1
...
有趣的是，我们可以将 \voffset 设置为任何值，输出也不会改变。问题是，为什么输出不会改变，\voffset如果它没有任何用处，为什么要设置？
注：\voffset用作\vglue
以下是test.tex和letterformat.tex。
这里是letterformat.tex：
\def\today{\ifcase\month\or
January\or February\or March\or April\or May\or June\or
July\or August\or September\or October\or November\or December\fi
\space\number\day, \number\year}
\raggedbottom
\interlinepenalty=1000
\hsize=6.25truein
\voffset=24pt
\advance\vsize-\voffset
\parindent=0pt
\parskip=0pt
\nopagenumbers
\headline={\ifnum\pageno>1
\tenrm To \addressee\hfil\today\hfil Page \folio
\else\hfil\fi}
\def\beginlinemode{\endmode
\begingroup\obeylines\def\endmode{\par\endgroup}}
\def\beginparmode{\endmode
\begingroup\parskip=\medskipamount \def\endmode{\par\endgroup}}
\let\endmode=\par
\def\endletter{\endmode\vfill\supereject}
\newdimen\longindentation \longindentation=4truein
\newbox\theaddress
\def\address{\beginlinemode\getaddress}
{\obeylines\gdef\getaddress #1
#2
{#1\gdef\addressee{#2}%
\global\setbox\theaddress=\vbox\bgroup\raggedright%
\hsize=\longindentation \everypar{\hangindent2em}#2
\def\endmode{\egroup\endgroup \copy\theaddress \bigskip}}}
\def\body{\beginparmode}
\def\closing{\beginlinemode\getclosing}
{\obeylines\gdef\getclosing #1
#2
{#1\nobreak\bigskip \leftskip=\longindentation #2
\nobreak\bigskip\bigskip\bigskip % space for signature
\def
{\endgraf\nobreak}}}
\def\annotations{\beginlinemode\def\par{\endgraf\nobreak}\obeylines\par}
\def\ps{\beginparmode\nobreak
\interlinepenalty5000\def\par{\endgraf\penalty5000}}
\def\up#1{\leavevmode \raise.16ex\hbox{#1}}
\font\smallheadfont=cmr8 at 8truept
\font\largeheadfont=cmdunh10 at 14.4truept
\font\logofont=manfnt at 14.4truept
\def\rjdletterhead{
\def\sendingaddress{R. J. DROFNATS, F.T.U.G.\par
PROFESSOR OF FARM ECOLOGY\par
TEX.RJD @ SU-SCORE.ARPA\par
\up[415\up]\thinspace 497-4975\par}
\def\returnaddress{R. J. Drofnats, Dept.~of Farm Ecology\par
The University of St.~Anford\par
P. O. Box 1009, Haga Alto, CA 94321 USA}
\letterhead}
\def\letterhead{\pageno=1 \def\addressee{} \univletterhead
{\leftskip=\longindentation
{\baselineskip9truept\smallheadfont\sendingaddress}
\bigskip\bigskip\rm\today\bigskip}}
\def\univletterhead{\vglue-\voffset
\hbox{\hbox to\longindentation{\raise4truemm\hbox{\logofont
\kern2truept X\kern-1.667truept
\lower2truept\hbox{X}\kern-1.667truept X}\hfil
\largeheadfont The University of St.~Anford\hfil}%
\kern-\longindentation
\vbox{\smallheadfont\baselineskip9truept
\leftskip=\longindentation BOX 1009\par HAGA ALTO, CA 94321}}
\vskip2truept\hrule\vskip4truept }
\def\makelabel{\endletter\hbox{\vrule
\vbox{\hrule \kern6truept
\hbox{\kern6truept\vbox to 2truein{\hsize=\longindentation
\smallheadfont\baselineskip9truept\returnaddress
\vfill\moveright 2truein\copy\theaddress\vfill}%
\kern6truept}\kern6truept\hrule}\vrule}
\pageno=0\vfill\eject}
这是test.tex：
\magnification=\magstep1
\input letterformat
\rjdletterhead
\address
Prof.~Brian~K. Reid
Department of Electrical Engineering
Stanford University
Stanford, CA 94305
\body
Dear Prof.~Reid:
I understand that you are having difficulties with
Alka-Seltzer tablets. Since there are 25~pills
per bottle, while the manufacturer's directions
recommend ``plop,~plop, fizz,~fizz,'' my colleagues
tell me that you have accumulated a substantial
number of bottles in which there is one tablet
left. % (See the 1978 SCRIBE User Manual, page 90.)
At present I am engaged in research on the potential
applications of isolated analgesics. If you would
be so kind as to donate your Alka-Seltzer collection
to our project, I would be more than happy to send
you preprints of any progress reports that we may
publish concerning this critical problem.
\closing
Sincerely,
R. J. Drofnats
Professor
\annotations
RJD/dek
cc: {\sl The \TeX book}
\ps
P. S. \ If you like, I will check into the
possibility that your donation and the meals that
you have been eating might be tax-deductible, in
connection with our research.
\endletter
%\makelabel
\end
答案1
该设置针对页面第一个之后。
如果我设置\voffset=0truept添加段落到信中以填充更多页面，我会得到
有了\voffset=24truept，我得到
